Pete, check out the Oz and African off roaders with their off road caravans,
the tin tents are about 12-14 foot, sometimes low profile with pop up roof
on same wheels tyres as the the tug.
then in terms of big caravans, look for airstream caravan safaris, these guys
back in 50S/60S were towing 20 -30 foot silver bullets round world, across
africa all in name of fun and destructive testing of the iconic trailers.
note the the yanks call caravans = trailers, and rallies = caravans.
2countries divided by a language etc.
got a great book on airstream history shows some of thes year or more long
trips, suspect there may be some utubes etc.
finally think some banger racing take tin tents round for fun, and stunts
have bee video'd taking a caravan round off road courses.