Four weeks from today, the world's top cyclists will set off on the men's Olympic Road Race. Simon Calder pedals his three-speed Brompton to Surrey.

Granted, when the planet's most spectacular scenery was being dished out, Surrey missed out on volcanoes, cirques and monoliths. But in the muscular shape of the chalk escarpment of the North Downs, the county south of London has a proxy for the Rockies. The River Mole, which rises somewhere south of Crawley and flows beneath Gatwick airport on its way to join the Thames, performs the same function as the Colorado in carving through a range to create a canyon. America's may be grander, but Surrey's canyon has the advantage that you can drive on the A24, travel by train or, crucially, cycle through it.

The Tour de France begins today, a touch surprisingly, in Belgium. After whizzing up, down and through the Alps and Pyrenees, the world's greatest cyclists will end their 2,174-mile competition at the Champs-Elysées in Paris on 22 July. For once, though, Le Tour will be trumped a few days later by a cycling event in south-east England: four weeks from today, at 10am on 28 July, the men's Olympic Road Race starts in the Mall in central London.

The 155-mile course steers south-west into the Home Counties, then swerves north-east to cut through the Surrey Canyon. At this point it has been largely flat – so to put the peloton through its paces, the cyclists must follow a National Trust sign directing them up a leafy lane. A century ago, this was private land, but in 1914 Leopold Salomons gave the hill, and its skirts, to the nation.

The good thing about cycle road racing is that someone with a three-speed Brompton folding bike can participate, at least before or after the event. While you can't imagine Formula 1 allowing someone in a Citroë* 2CV to test the course at Monaco, nor a jogger being allowed to try out the 400m track in the Olympic Stadium, there is nothing to stop anyone with two wheels and a bell to blaze a trail for the world's best cyclists. Except fear itself. And if the prospect is making you feel a bit wobbly, the Stepping Stones pub at the foot of the hill has a sign reading: "Fill your water bottles and use our toilets free" as well as plenty of brews to help stiffen resolve.

The village of Mickleham is base camp for the mission. From here, take the zig-zag road, which has an official name: Zigzag Road. The map reveals a couple of classic Tour de France hairpins. But it turns out to be a very English avenue that creates a verdant gallery, as oak and birch merge in a tangle of branches and creepers and climbers.

The summer sky, when it steals through, illuminates the blossom still clinging to the trees after the bitter June breeze has swept through (attested by a scattering of branches across the road). The surface is mostly a cyclist's dream: rather than the coarse, pot-holed roads that make cycling in Britain only marginally better than pedalling across the surface of the Moon, this is a smooth river of fine Tarmac that curls as it climbs. "Humps for 250 yards" turns out to be an idly threatening sign.

With some altitude under your tyres, you can look across the valley and see a slice of what George Orwell called (on the last page of Homage to Catalonia) "probably the sleekest landscape in the world". A single, naked tree – a homage to Arizona? – stands starkly against England's green and pleasant land. And did those feet, in ancient time, walk upon these pastures green? Some of them did. The Pilgrims' Way from Winchester to Canterbury passed close by. Today, the North Downs Way between Farnham and Dover traverses Box Hill. What with the Surrey Cycleway and the National Cycle Network Route 22, this patch of the county carries a heavy burden of outdoor enthusiasts.

Zigzag Road is also open to vehicles. Bike riders are urged by little plastic signs to "Cycle in single file", which may not happen on the Road Race day, and indeed didn't happen on my Olympian bid. I don't know if Nick Groves and Tom Middleton, both from south-west London, had been slip-streaming me for long, but just past the sign leading to the Pinehurst Rest Home (no, I wasn't tempted), they overtook me. I caught up with them at the top of Box Hill, but only because they had stopped to rest after an even more testing ride than mine. Together, we studied the map of the Olympic Road Race.

"This is the good bit," indicated Nick with a swoop of his hand around the large, leafy loop they had just followed, from Hampton Court, through stockbroker Surrey – Weybridge, Woking, Guildford – before whipping around to the Surrey Canyon.Oh no it isn't, I silently thought: this much smaller sub-loop, up to Box Hill and back down to the A24, is all you need. Indeed, the men will get a chance to enjoy it no fewer than nine times – the best way to replicate a stage in the Tour de France and get the mileage count up without leaving the Home Counties. (The Olympic women go around only twice.)

Unlike the competitors, I took a break at Box Hill – and discovered a joyful viewpoint where south-east England's intricate beauty is revealed in all its gentle glory. You would never know this is one of the most crowded corners of Europe. Unravelling into a gentle haze is a patchwork of meadows threaded through with "The slow-moving streams bordered by willows" beloved by Orwell. "Gatwick 8 miles," claimed a sign, but up here in the Surrey stillness it seemed implausible that the world's busiest single-runway airport is three minutes' flight ahead, and that the M25 rumbles close by.

Most peaks offer little of interest besides the view. Not so Box Hill, venue for one of southern England's more unusual tombs. A gravestone commemorates Major Peter Labillière, "An eccentric resident of Dorking" (is there any other kind?), buried head down in 1800, apparently because "all the world is topsy-turvy". Box Hill also boasts a Victorian fort – part of the London Defence Scheme to protect the capital from an enemy. (That'll be the French, then.) Along with a dozen other redoubts strung out across south-east England, it harnessed the terrain to provide hope for the heart of the Empire.

Beyond the fort, the Olympians will find themselves in an English village, also named Box Hill ("Elev. 687 ft."). It has a cricket pitch and a housing estate ambitiously named "Roof of the World". To reach the Roof of the World, no need to fly to Tibet or Bolivia: bus 516 from Dorking does the trick. But it is more fun to cycle, especially when the course turns north and downwards. I took more note of the "Beware Steep Descent" sign, and the 20mph limit, than the Olympic cyclists will do on 28 July. I sat back and watched the landscape open up into daisy-strewn meadows decorated by a time-worn barn or two. Then, down through a tunnel of foliage that guides the cyclist to the Mole Valley and back to real life with a bump. Welcome to Leatherhead.

Travel essentials

Getting there

Box Hill & Westhumble station is served by Southern trains from London Victoria, Clapham Junction, Dorking and Horsham (08457 48 49 50). Bus 516 serves the top of Box Hill, from Dorking, Leatherhead and Epsom. The nearest airport is Gatwick.

Staying there

The Burford Bridge Hotel (020-7660 0684;, at the foot of Box Hill, has doubles from £99 in July, excluding breakfast, but no availability on 27 and 28 July (the nights before the Olympic events).

Find properties along the route

Properties for sale in Crawley

Properties for sale in Box Hill

Properties for sale in Weybridge

Properties for sale in Woking

Properties for sale in Guildford

More information