Interesting article, thanks for posting it.
According to Wikipedia
....... the origins of travel trailers and caravanning can be traced back to traveling Romani people ('Gypsies'), and showmen who spent most of their lives in horse drawn trailers.
The world's first leisure trailer was built by the Bristol Carriage Company in 1880 for Dr. W. Gordon-Stables. It was an 18 ft. design, based upon their Bible Wagons, which the Doctor named "Wanderer
There's even a picture of a 5-wheel Scamp
in the Wikipedia article!
Wikipedia Travel Trailers