So this is what they mean by park and ride

For a truly American experience hire yourself an RV.

The American Dream takes many forms but at its most evocative it begins with a journey. From the pioneers' covered wagons to Jack Kerouac's petrol-fuelled odyssey, free-spirited individuals have ridden back and forth across the American landscape in search of, above all, personal freedom. In the States today there is a growing band of travellers who cruise the land in "recreational vehicles", motor homes that range from modest camper vans to travelling palaces that can come complete with a Jacuzzi or even a garage. "In a modern RV you're travelling with all the comforts of home," says Joe Laing of El Monte, one of the largest RV rental companies. "But it's really about the freedom to go where you want, when you want, and to stop and pull out a beer." This last freedom is what particularly appealed to me.

One word had persuaded me to sign up to an RV holiday in America: boondocking. Boondocking is RV slang for parking overnight without amenities, probably on an unofficial site. Boondockers eschew RV parks and campsites, preferring truck stops, side roads, back-lots, even the car parks of supermarkets. Wal-Mart, in particular, has a welcoming policy towards RVers. Boondocking spoke to the vagabond in me. With three weeks to explore California, who knew what I might find?

My travelling companion and I were RV virgins (I don't even drive), and our first close sighting of an RV was daunting. As we pulled in to the El Monte RV rental garage in Los Angeles, elephantine motor homes nuzzled the wire fencing like big game in a safari park. An induction video introduced us to our beast, to the hoses, valves, switches, pumps and different fuels and batteries that must be deployed to run your home on wheels. The rhythms of RV life are liquid, governed by the ebb and flow of evacuating your black (waste from the lavatory) and grey (waste from the sinks and shower) holding tanks and taking on fresh supplies of water and petrol.

Our RV was one of the smaller ones (23 feet, C class - which means it looked like a converted van). It had a shower, a loo, a table flanked by cushioned benches, a fitted kitchen and picture windows that gave each of its two double beds (one above the driver's cab) a panoramic view. Having bought a small Union Jack, which fluttered ahead of us on the bonnet, we set out.

Our first night on the road we drove through Los Angeles' sprawling suburbs until the only lights around us came from other vehicles, then boondocked in a truckers' rest stop. We woke up to a new world: desert, a shimmering highway, and a solitary store where we bought a country music tape and fresh milk for our coffee, which we drank easing back and forth on the store's creaking wooden porch swing. The tape was titled The New Tradition Sings Old Tradition, and in a way this was what RV travel was: a modern version of an older type of journey. In an RV you experience – not just visit – landscapes, people, the weather, in ways that have been done away with by most modern forms of travel.

In America that experience begins with the roads. There are roads that run straight for miles, carving through granite, barrelling through mountains, before throwing a loop around a bluff of land small and soft as a breast. There are roads that buck and twist like a bronco threatening to toss you down precipitous flanks; night-time roads, when it is just you and one other car many miles ahead. Along roads such as these we drove past conifers, cacti, tumbleweed; through canyons and sinister fogs; beneath skies that turned from show-girl pink to purest blue, then filled with dark clouds. We drove across deserts, beside a boiling ocean and into mountains. We stopped to walk up sand dunes and across moonlit salt lakes, to bathe in hot springs, to sit beside a waterfall and watch the water turn to ice. We paused to look at sea lions, buffalo, coyote and, for a enchanted half hour, to listen to skylarks.

In a single day we made breakfast at the highest point in the USA (Mount Whitney) and cooked dinner at the lowest (Death Valley). We spent nights boondocked beside Domingo's Mexican restaurant in Boron, on the forecourt of the Amargosa Opera House in Death Valley Junction, behind Buck Owen's Crystal Palace in Bakersfield, where we had danced to live country music, and in a rest-stop across from the Searchlight Nugget Casino, where a couple who had got lucky bought the entire bar a drink.

We discovered that boondockers are not welcome everywhere. In one small town, Shoshone, we were encouraged towards the RV park amid chilly politeness and tales of RVers being run off nearby land. At a Wal-Mart north of Santa Clarita, staff said we were welcome to stay but a security guard working for the owner of the shopping mall moved us on. In some places local ordinances prevent RVs from overnighting.

Our best days on the road evolved unplanned. Days when we would step from bed into the kitchen, filter coffee, then drive all day along strange roads all the way to sunset, when we would stop, take a beer up on the roof and watch the sun go down. Afterwards, we would drive on again until dinner, park, cook, eat, and talk about the things we had seen that day. Then we would fall in to bed with the wind blowing and howling around our RV, rocking us like babies into sleep, the promise of morning in our minds.

The Facts

Getting there

British Airways (0845 77 333 77) offers return flights in August from £566.30. Virgin (01293 450150; www.virgin-atlantic.com) offers return flights in August from £556.30.

Being there

Frances Dickenson rented an RV from El Monte RV (001-562-483-4969; e). A 20-day rental costs from $343 (£216).

Further information

For information about campgrounds and RV parks visit www.koakampgrounds.com, www.tldirectory.com and www.gocampingamerica.com. Some of the best locations are in National Parks. For details, visit www.nps.gov . Sites cost from $10 to $50 per night.