How quickly can the adventures begin?
Within an hour of landing at Sydney airport, you can head into town to be breathalysed, go through an airport-style security check, sign a form promising not to remove any part of the Sydney Harbour Bridge, and dress up in an attractive grey romper suit. The is the Sydney Harbour Bridge Climb (00 61 2 8274 7777; www.bridgeclimb.com), which celebrates its 10th birthday this year. For a decade adventurous visitors have been attracted by the chance to clamber along catwalks and up ladders to the summit of "the Coathanger", as the iconic bridge is popularly known. The view of the harbour and Opera House from 134m above sea level is worth every wobble – and the A$199 (£80) tag.
For a more technical adventure, the new "Discovery Climb" costs the same but takes you inside the workings of the bridge.
The essential road Adventure?
Make tracks to "The Track", or the Stuart Highway as it's officially known, which runs for just over 2,800km from Port Augusta in South Australia, to Darwin, the capital of Northern Territory. In UK terms, this is the equivalent of Land's End to John o' Groats – and back again. The Stuart it commemorates is John McDougall Stuart, a Scottish explorer who became the first European to cross the continent from south to north in 1866, and most modern travellers go in the same direction. The trail starts amid rolling hills and vineyards in South Australia, passes through desert, and finishes in the Tropics of the Northern Territory.
Along the way you can spend an adventurous night at Coober Pedy, Australia's opal-mining centre, where the summers are so hot and the winter nights so cold that half the population lives in purpose-built dugouts. Midway between Adelaide and Alice Springs, it's a convenient overnight stop, and you can experience the eerie, sleep-inducing silence of subterranean life by putting up at the Desert Cave Underground Hotel (00 61 8 8672 5688; www.desertcave.com.au), where a double room costs A$198 (£86) per night, including breakfast, which is served back in the daylight, above ground. At the mine office you can buy a Precious Stone Prospecting Permit for around A$60 (£24). This entitles you to search for opals in a plot half the size of a football field for anything up to a year.
Spend a day or two at Alice Springs, close to the centre of the continent and within striking distance of Uluru (Ayers Rock). Alice, the capital of Australia's outback, is an appealing place with plenty of modern amenities but with a strong sense of its aboriginal heritage: the indigenous population is the largest in Australia. There are several interesting museums and a magnificent nature park on the outskirts that unlocks the wonders of the "Red Centre". The Alice Springs Desert Park (00 61 8 8951 8788; www.alicespringsdesertpark.com.au) opens 7.30am-6pm daily; A$20 (£9). The visitors centre at Gregory Terrace (00 61 8 8952 5800; www.centralaustraliantourism.com), which opens 8.30am-5.30pm on weekdays, and 9am-4pm at weekends, will help with essential information, accommodation and maps.
Back on the highway, look out for light aircraft on the carriageway: the road is used as an emergency landing strip by the Royal Flying Doctor Service.
The last great sight on the northbound route is Litchfield National Park, with its giant waterfalls and monumental termite mounds. Plunge in for an adventurous day or two exploring the dramatic landscapes and cooling waterholes, just before the first glint of the Timor Sea on the horizon signals journey's end. All the usual multinationals will rent you a car; through Apex (00 61 800 3260 5466; www.apexrentacar.com.au), a one-way from Adelaide to Darwin costs from A$492 (£214) for a fortnight, the minimum rental period allowed.
Time is pressing. Any adventurous journeys of three or four days?
Victoria's Great Ocean Road (www.greatoceanroad.org) is only 243km long, but is one of the world's most scenic drives, as it weaves a sinuous path around fractured cliffs and headlands, with the surf of the Southern Ocean only a kangaroo's leap below. The trail starts south of Geelong, at the breezy surfing resort of Torquay, and extends as far as Nelson, near the border with South Australia. It was hewn out of the rock as a job-creation scheme for servicemen returning from the Great War, and has been designated as an official war memorial to those who fought and died in the conflict. The highlights are the Great Otway National Park, rich in wildlife and containing one of Australia's most luxuriant forests, and the Twelve Apostles, an impressive scattering of limestone monoliths wrenched from the cliff-face by violent sea and wind erosion.
The most challenging way to make an adventure of the Great Ocean Road is to combine the drive with a section or two of the Great Ocean Walk (www.greatoceanwalk.com.au), which follows the south coast for 91km from the resort of Apollo Bay to Glenample Homestead, taking in parts of the coastline that the highway cannot reach. The walk is designed in short, easily accessible stages, and includes a spectacular loop around the mainland's southern extremity, Cape Otway, where the light-station was the first glimpse of land for many an ocean-going traveller from Europe. At comfortable pace, it takes eight days to complete a route that combines outstanding coastal and forest scenery, and promises many a sighting of wallabies, koalas, possums, grey kangaroos – and long-forgotten shipwrecks, remnants of which are still visible on the ocean shelf. The grand finale is the lovely, sandy stretch to the Twelve Apostles.
To see more of southern Victoria, the Great Ocean Road forms a part of the Great Southern Touring Route (www.greatsoutherntouring.com.au), a circular drive of nearly 800km that starts and finishes in Melbourne, and shows off the state's impressive diversity. After thrillingly skirting the ocean, with the possibility of a whale-sighting at Warrnarmbool, the trail turns inland towards the Grampians, a range of mountains that rise unexpectedly from the flat pasture, with woodland walks leading to waterfalls and lakes, ancient aboriginal sites and a series of fine look-outs from the ridges above Hall's Gap.
Next, the route heads east to the goldfield region, where tens of thousands of prospectors created a California-style rush when gold was discovered in 1851. Over the next 50 years, Ballarat became a thriving, elegant city, and the miner's camp at Sovereign Hill has been imaginatively reconstructed to show how the pioneers lived. A day's pass to the outdoor museum (00 61 3 5337 1199; www.sovereignhill.com.au), which includes a Victorian-era dinner and a spectacular evening show, costs A$103 (£45) per adult. The final section of the route takes in the pleasantly bohemian spa town of Daylesford, before returning to Melbourne. Allow four days to get the most out of the drive.
The best rail adventure?
When the rail link between Alice Springs and Darwin was completed in 2004, finally connecting the north and south coasts by train, Australia became the first continent to be spanned by railways to the four points of the compass. The vital statistics of the two longest rail routes are as astonishing u o as the contrasting landscapes traversed twice a week by the Indian Pacific (Sydney-Perth) and The Ghan (Adelaide-Darwin). The east-west journey, in particular, challenges the imagination of anyone brought up in a small country. Its 4,352km length, which includes a section of track that runs perfectly straight for 478km across the mostly featureless Nullarbor Plain, which is itself six times the size of Belgium. The journey takes 64 hours, spanning three overnights.
The Ghan, named after camel-drovers from Afghanistan who pioneered travel through the outback, takes an average of 47 hours to cover nearly 3,000km of track across the Red Centre, with reconditioned, stainless-steel carriages that offer a measure of comfort but could never be described as luxurious. Many train-goers break the journey at Alice Springs to make a side trip by road to Ayers Rock. Both are operated by Great Southern Railways (00 61 8 8213 4592; www.gsr.com.au), which provides different grades of accommodation, ranging from airline-style reclining seats (bring your own rug and pillow) to private cabins with en-suite bathrooms, personal service and complimentary meals. On The Ghan, single fares are A$690 (£300) for the no-frills option, rising to A$1,920 (£840) for first class. On the Indian Pacific, the equivalent fares are A$680 (£297) and A$1,790 (£780) respectively. Internal flights are considerably cheaper, especially if you book some weeks in advance, but the memory of a routine air-hop from Sydney to Perth is unlikely to remain with you for the rest of your life.
A classic river adventure?
Originating in the Snowy Mountains of New South Wales, the Darling river meanders through the outback to join the Murray river on a 2,739km journey to its rendezvous with the Southern Ocean near Adelaide. It's the third-longest navigable river in the world after the Amazon and the Nile. In the decades before the First World War, the river swarmed with paddle-steamers, and numerous vessels – restored originals or reproductions – are doing service, evoking the river's golden age as Australia's version of the Mississippi. At the sunny, oasis town of Mildura on the Victoria-NSW border, the PS Melbourne, built in 1912, is one of the last remaining steam-powered ships licensed to carry passengers. Two-hour cruises leave Mildura twice a day (10.50am and 1.50pm); the fare is A$20 (£8.70). The largest and best-appointed of the paddle-steamer fleet is the Murray Princess – a modern reproduction – which does a variety of longer river journeys from its base in Adelaide. Fares for a three-night weekend cruise, based on two sharing an indoor cabin, start at A$784 (£340), including bus transfers and some excursions at its ports of call. Packages are available from UK-based Blue Water Holidays (0845 226 2475; www.bluewaterholidays.co.uk).
For excitement, head for the riverside town of Echucam, whose local hero is Brett Sands – former barefoot waterskiing world champion. He now runs a watersports centre (00 61 3 5482 1851; www.brettsands.com) where complete novices can master the basics of wakeboarding or waterskiing in a day for $A$220 (£88).
Time to put on the walking boots
Everywhere you go in Australia, the joys and benefits of outdoor life are enthusiastically promoted. Tourist centres from Perth to Cairns will fill your knapsack with brochures and maps detailing walks, cycle routes and bridleways. The most ambitious project is the Bicentennial National Trail, a collaboration by Queensland, New South Wales and Victoria to create a route through the backwoods of all three states for the exclusive use of everyone who eschews motorised transport: only walkers, horse-riders and mountain-bikers need apply. From north to south, the trail runs for an incredible 5,330km, from Cooktown in tropical Queensland, following the course of the Great Dividing Range of mountains through NSW to Healesville in Victoria, following historic coach and cattle-droving routes and crossing 18 national parks. Experienced trekkers are attracted by its length; first-timers by its infinite variety.
Lightly populated Tasmania boasts one of the world's great wilderness walks. The Overland Track covers 65km of the World Heritage Area across the mountainous spine of the island from jagged Cradle Mountain (1,545m) to stunningly beautiful Lake St Clair, the deepest in Australia, at 200m in parts. With a fair wind, the trek takes six days, but extra time should be allowed because of Tasmania's fickle weather. Despite the uncertainties, 9,000 walkers complete the journey every year, and numerous sections of boardwalk have been put in to prevent the flat expanses of buttongrass turning into muddy swamps. There are bushwalker's huts at the five designated overnight stops, with rainwater tanks, camping platforms and toilets. In summer (1 November-30 April) walkers must book in advance (00 613 6233 6047; www.overlandtrack.com.au), head in one direction only (north to south) and pay a fee of A$150 (£65) towards the maintenance of the walkway and shelters.
For those who prefer less beaten tracks, there are numerous side-trails from the Overland Track to explore, although guides are recommended for any serious diversions. One highlight is Mount Oakleigh, halfway along the track. To reach the summit you pass through ancient rainforest, myrtle and sassafras trees before levelling out on a high alpine plateau, from where the views are extraordinary.
Western Australia's extreme hiking challenge is the 1,000km Bibbulmun Track, from Kalamunda in the Perth Hills to Albany on the wild south-west coast. It has 48 designated campsites, roughly 20km (or a comfortable day's walk) apart. Facilities are free, but sites are allocated on a first-come, first-served basis, so long-distance walkers should carry tents and fuel stoves. Equipment can be hired from the Bibbulmun Track Foundation in Perth (00 61 8 9481 0551; www.bibbulmuntrack.org.au) – a basic kit of backpack, sleeping bag and lining, mat, stove and tent costs A$115 (£50) per week.
For off-road cyclists in Western Australia, the Munda Biddi Trail (00 61 8 9481 2483; www.mundabiddi.org.au) is the toughest challenge: more than 300km of rough track between Mundaring, north-east of Perth, through eucalyptus forest and bushland to the provincial town of Collie. A day's hire of a good mountain bike costs around A$22 (£9.50).
Any tropical adventures?
One of the Great Barrier Reef's delights is Hinchinbrook Island, a 37km-long mountainous slice of tropical wilderness that is 50 minutes by ferry from the two small ports of Cardwell and Lucinda, halfway between Cairns and Townsville. There are daily services to the island (return fare A$96/£41) between April and October. Hinchinbrook is the largest island on the reef, with rainforests, mangrove swamps, and a pronounced backbone topped by Mt Bowen (1,121m). Separated from the rest of the island by a long spit of sand, the upmarket Wilderness Lodge (00 61 7 4066 8270; www.hinchinbrooklodge.com.au) is the only permanent settlement.Spend the night in a tree hut or beach cabin. Sleeping up to four people, a beach cabin costs A$225 (£98) per night. The outstanding hike is the 32km Thorsborne Trail along the eastern edge of the island, which takes four days at a comfortable pace. There are several campsites, often near streams and waterfalls. To preserve the wilderness, the number of walkers is restricted to 40, so a permit is required, costing A$4.50 (£2) per night. Apply online at www.qld.gov.au/camping.
Tourism Australia: 0870 556 1434; www.australia.com.
Adventure with a tee
Driving the Eyre Highway, which links Western and South Australia via the Nullarbor Plain, will take on a new meaning in November when the world's longest golf course opens. The Nullarbor Links (www.nullarborlinks.com) will stretch across three time zones and 1,365km, from tee-off in Kalgoorlie (WA) to the 18th at Ceduna (SA).
Visitors will be able to take their time crossing the desert and discover remote outback towns. Some holes will be "lent" by towns with courses; others will be purpose-built, and each stop will promote a local attraction, from whale-watching to fossil beds.
Bridge & Wickers (020-7483 6555; www.bridgeandwickers.co.uk) is offering packages before the "course" is even finished.
Ten nights in a two-berth camper van, plus return flights from Heathrow to Perth and back from Adelaide, is £1,235 per person.
Trails of the cities
Sydney's glorious location is best appreciated from the cliffs and headlands overlooking the eastern shore between Bondi and Bronte Beaches. There's an easy, well-marked 3.5km route for walkers and joggers, which drops down to sea level at Tamarama, the most glamorous sun-and-surf locale of all. There are plenty of refreshment stops along the way, including the Swell Café, which specialises in hearty breakfasts. Pumpkin omelette, anyone? Beyond Bronte Beach, the trail continues, less spectacularly, to Coogee (6km) and Maroubra (12km), from where there are buses back to the city.
Melbourne claims to have the largest population of cyclists outside Beijing, and makes generous allowances for them. All the main roads into the centre have cycle lanes, and the best of several excellent off-road routes is the Yarra River Trail, starting at the mouth of the river and ending on the south bank, in the heart of the city. Half-day or evening guided tours of the trail cost A$48 (£21), including a drink. Contact St Kilda Cycles (11 Carlisle Street; 00 61 3 9534 3074; www.stkildacycles.com) for bike hire and booking.