Rocky mountain high: Swap the luxury cocoon of American ski packages for the freedom of a DIY trip to Colorado's slopes, says Chris Gill

My few skiing trips to the States have mostly been of the conventional, packaged kind, involving a series of luxurious cocoons - you step into your smart minibus at the airport, out of that into your smart resort hotel, and then go skiing. Some days later you repeat the process in reverse.

But I've often thought that I'd like to make more of an adventure out of a trip to the Rockies. Not a wilderness experience with snowshoes and survival rations, just something with a slightly exploratory feel: a hire car (or an airpass 'rover' ticket), no advance reservations, a variety of ski resorts on the agenda and some contact with the country outside of those ski resorts - eating in roadside diners on the way to the next resort, for instance.

The obvious target for this sort of trip is Colorado, where many of America's biggest and best resorts are concentrated, mostly within driving distance of the gateway airport, Denver.

The prime destination, for most skiers, is neo-Tyrolean Vail - from many points of view the most impressive resort in the States, and less than 100 miles (on good highways) from Denver. Equally convenient, and in some ways equally compelling, is the string of resorts that operate under the Summit County umbrella - Breckenridge (a dinky, restored mining town), Keystone, Arapahoe Basin and Copper Mountain.

Aspen is Vail's great ritzy rival - another restored mining town, but much more affluent than Breckenridge. In winter it is about another 100 miles' driving from Denver, and rather isolated for car touring purposes. Crested Butte (a simple mining town - 'the way Aspen used to be') is only 20 miles south over the hills, but more than 200 miles by road. Since it has an airport not far away at Gunnison, an excursion by air is a possibility. And both Aspen and Gunnison are accessible from Denver by air.

Telluride, another old mining town in the south-west of the state, is gaining a growing following in Britain - not least because of its spectacular mountain scenery. You are more likely to get to it by plane than car.

Denver is the main point of arrival for Rockies-bound skiers. It opens a huge new airport in December on a new site north-east of the city - the 'wrong' side for skiers' convenience, but (they say) adding only 20 minutes to journey times via the existing Stapleton airport. For the British, Denver remains the only Rockies airport with non-stop direct flights - five times weekly with Continental Airlines from Gatwick.

Continental's flights could scarcely be better timed. Outbound flights (daily except Monday and Thursday) leave at 12.55pm and arrive nine hours 25 minutes later at 3.50pm local time - so there's plenty of time to get to Gatwick in the morning, and to your resort in the afternoon. Return flights (daily except Sunday and Wednesday) depart at 7pm and have you back at 11am the following day.

Winter fares start at pounds 320 return (book 21 days in advance, stay at least seven days). Weekend travel adds a supplement of pounds 20, and between 11 and 24 December the fare is pounds 479.

Continental also operates indirect flights via Houston or Newark. It charges the same fares as on the non-stop service. But you can also book flights through tour operators, and I've found that their prices for the indirect services can be much lower, at least in the Christmas peak season.

Tour operators also offer car hire at highly competitive rates - which will come as a pleasant surprise if your knowledge of skiing car hire is confined to Geneva, Zurich or (worst) Turin. Small hatchbacks can be had for around pounds 110 a week, and even full-size saloons do not cost much more unless you opt for luxury.

For a wide-ranging tour - within Colorado or into the neighbouring states of Wyoming, Utah, and New Mexico - airpasses are well worth investigating. For example, if you fly out on Continental you can buy a pass for three internal flights for pounds 240 - and you could travel as far as California.

Car hire and flights can be successfully combined by using 'open-jaw' arrangements - perhaps driving from Denver via Vail to Aspen, and flying back to Denver. Continental will quote return fares to various destinations; to arrive at the open-jaw cost, average the fares for the two airports.

Provided you can contemplate indirect flights involving two- or three-hour pauses, there are several other airlines that can get you from London to Denver - Delta via Cincinnati, United via Newark, or American via Dallas.