(FORTUNE Magazine) – Can't get that cabana in Lyford Cay? Somebody else booked the company lodge in Aspen? Do what Americans are doing in greater numbers than they have in 15 years: Buy a travel trailer or motor home, and hit the road. Deliveries of recreational vehicles in June were 20% higher than a year ago. Industry giants Fleetwood Enterprises of Riverside, California, and Coachmen Industries of Elkhart, Indiana, are both operating near capacity. A greater interest in family outings and wholesome recreation helps explain the surge. ''Younger people, not just retirees, want to escape the city and get back to the simple life,'' says David J. Humphreys, president of the Recreation Vehicle Industry Association. ''We don't just have the wind at our back; we have a hurricane.'' The ill wind of difficult economic times is still a force, however. So most of the boom has been at the the low end of the market. Fold-up camping trailers, which are towed behind cars and cost from $2,500 to $10,000, sold at a rate 52% higher in June 1993 than in the same month a year ago. The Gunseors of Lewiston, Idaho, invested $7,000 for a new 12-foot trailer and vacation at a rural campsite not far from home with their five children, ages 2 to 13. Bonnie Gunseor, 36, is thrilled to have graduated from a tent. ''You don't drown when it rains,'' she says. If she really wants to get far from the storm she can move up to the top of the line. For $115,000, Winnebago Industries sells a 35-footer with two TV sets, an icemaker, and video cameras in the rear that help the driver back up.