Where can we find campsites in the Caribbean?

QWe want to visit the Caribbean over October half-term with our two children, aged 13 and 16. We would like some activities and are also interested in camping, maybe staying in a hotel for the final few days. Can you suggest which island to head for?

Q We want to visit the Caribbean over October half-term with our two children, aged 13 and 16. We would like some activities and are also interested in camping, maybe staying in a hotel for the final few days. Can you suggest which island to head for?

L Sargent, Sutton

A Travelling to the Caribbean over half-term will not be a budget option I'm afraid, even if you opt for campsites rather than hotels. Flights during October come in at around the £500 mark. Also, the hurricane season may not have blown itself out by then, so you could still feel a few storms tugging at the guy-ropes. Those concerns aside, there are a few places I would suggest. St Lucia's National Trust (001 758 459 04540, www.slunatrust.org) recently opened the first campsite at Anse La Liberté – midway along the west coast, 25 miles south-west of the capital, Castries, and a 15-minute drive north from Soufrière, the oldest town on the island. To camp overnight on an elevated platform (with double tent provided) costs £27 per night, or £20 on the ground.

The campsite offers a variety of activities, including guided treks along rainforest trails and watersports. The neighbouring fishing village of Canaries, and nature trails, are within easy reach.

St Lucia is also great for mountain biking, or "jungle biking" as it is known locally. Bike St Lucia (001 758 459 7755, www.bikestlucia.com) has cycle trails set in 400 acres of rainforest, located in the grounds of an 18th-century French colonial sugar mill on the island's west coast. The cost is US$89 (£59) for a day's jungle biking, including all equipment, lunch and free use of snorkelling gear for those who can't drag themselves from the centre's secluded beach. Island Bike Hikes (001 758 458 0908, www.cyclestlucia.com) also offers bike tours of St Lucia from $58 (£39). One option is a route through the island's richly forested interior, making use of old mule trails.

As far as hotel accommodation goes, St Lucia has numerous family-friendly resorts. A good contrast would be to move to the slim northern tip of the island, where the Caribbean and Atlantic coasts meet, and stay at the popular Windjammer Landing hotel (0800 316 9797, www.windjammer-landing.com). A two-bedroom villa starts from £280 per night in October. Return flights direct to St Lucia with Virgin Atlantic (01293 747 747, www.virgin.com) in October will cost around £521 per adult; unfortunately your children are too old to qualify for reduced prices. For further information contact the St Lucia Tourist Board in London (020-7431 3675, www.stlucia.org).

Further north, the French island of Martinique offers a good selection of places to pitch your tent. As one of the more developed Caribbean islands, it also has plenty of places for grocery shopping for self-caterers. Anse-a-l'Ane near Trois Ilets (00 596 596 68 31 30) is one of several camping companies offering well-equipped sites. Beside the beach, the site costs €21 (£14) per tent, per night (sleeping two adults and two children). Activities on offer include snorkelling and sailing (the latter in Martinique's enormous marina).

To reach Martinique, fly from one of several UK airports via Paris (where you must switch airports) with Air France (0845 0845 111, www.airfrance.co.uk). Fares cost from £471 return in October. Alternatively, fly from Heathrow to St Lucia with BWIA (020-8577 1100 www.bwee.com) from £520 return and on to Martinique with Air Caraibes (00 590 590 82 47 00, www.aircaraibes.com), for an additional £142 return.

One of the lesser-developed islands in the US Virgin Islands, St John, also offers an excellent Caribbean camping experience. The Virgin Islands National Park campsite (001 340 776 6201, www.virgin.islands.national-park.com) provides bare sites, permanently pitched tents or lodge units. A tent with a maximum of four sharing costs US$58 (£38) per day. Advance booking is recommended. The site also organises outdoor activities, including the junior rangers' programme where children can learn about local wildlife.

Following your nights under canvas, a touch of luxury can be found at the Concordia Studios (001 340 693 5855), an eco-friendly lodge about half-an-hour's drive from Maho. Each lodge offers twin beds and a queen-sized futon, and costs from $85 (£57) per night based on double occupancy, plus $15 (around £10) extra per night per extra guest.

Sunsail (023 9222 2226, www.sunsailflights.co.uk) operates direct flights from Gatwick to St Thomas every Friday (the return flight goes via Antigua). Expect to pay around £425 per adult and £400 per child return. St Thomas is a 45-minute boat ride from St John ($3/£2).

For more details, contact the Caribbean Tourism Organisation (020-7222 4335, www.caribbean.co.uk).

Q Our boys, aged 10 and 13, got terribly excited last summer when we were driving across America and passed a sign showing the Continental Divide in the Rockies. I understand that everywhere east of that dividing line, the water flows into the Atlantic, and everywhere west to the Pacific. This year we're driving down to Italy. I assume there's a similar division between, say, the Rhône and the Rhine or possibly the Danube. Can you tell us where, so we can look out for it?

G Lewis, Coventry

A In the US, the "Great Divide" runs along the backbone of the Rocky mountains, making it pretty hard to miss. It's all pleasantly straightforward; with an ocean to the east, another to the west and a mountain range in between, water has just two ways to go.

Things are a lot more complicated in Europe, according to every geographer I talked to at UK universities. Rather than neatly following the line of the mountains, the divide meanders across Europe, making it far more difficult to pinpoint, and distinctly less exciting than its American counterpart.

"There are a number of seas into which rivers can flow and a complex arrangement of mountain ranges," says Bob Parry, who is curator of maps at the University of Reading. He does not spend his holidays looking for such a line: "Actually to define the divide would be extremely difficult."

The Alps, he concedes, are one possibility, as the mountain range forms central Europe's major east-west watershed. To the north, the Seine, Rhine and Elbe flow into the North and Baltic seas. On the other side, the flow is to the south – the Po to the Adriatic, the Danube to the Black Sea and the Rhône into the Mediterranean. The problem with the theory, however, is that the sources of both the Rhône and the Danube lie north of the Alps (see the map on page 7 for the Rhône's origins).

That said, some of the highest and most scenic points of the divide are in the Bernese Oberland, a mountain range between Lake Geneva and the St Gottard Pass in Switzerland. Driving along the pass towards the Italian border is sure to provide some spectacular scenery and one or two opportunities to try to pick out the divide.