For the first time, Americans had the leisure time, the machinery and the all-weather roads they needed to tour the country. They were encouraged by such visionaries as Glenn Curtiss, who set out to travel in the most homelike environment he could build.

He created a lavish "motor bungalow" as early as 19l9. In 1928, he revamped his design and called it the Aerocar. It looked, on the outside, like a fancy horse trailer. It featured four berths, a galley, running water and an "observatory cockpit with a glass roof," according to Wheel Estate, and cost a whopping $2,500.

A more proletarian option, at only $395, was the Covered Wagon. A Minnesota bacteriologist named Arthur Sherman designed and began mass-producing this trailer, which was compartmentalized like a dollhouse, in 1929, after a nightmarish family vacation during which he spent an hour wrestling with an uncooperative tent trailer in pouring rain.

Made of plywood, the Covered Wagon appeared boxy, but the interior was comfortable and plushly appointed. Sherman started the business in his garage and by 1936 had become the largest manufacturer in the travel-trailer industry.

Above quoted from 'House Trailers' by Chiori Santiago - an article in the June, 1998 'Smithsonian.'