The sales of recreational vehicles rose dramatically last year, and it’s easy to see why. The recreational vehicle is the apotheosis of America's love affair with comfort, convenience and freedom — a domestic paradise in miniature. Modern RVs come equipped with computerized automatic leveling systems, so that even the wildest campsite can be made as flat as a suburban lot. They are air conditioned, fitted out with refrigerators, microwaves and every convenience of modern life. When RV owners want to get closer to nature, they can watch a wildlife program on public television. Most camp sites offer hook ups, where they can plug into electric power, water, waste disposal, cable TV and dry martini lines. A fully hooked up RV looks like a hospital patient in intensive care.