...Having dissected a caravan, I can confirm that it had a steel chassis, wood frame, ally panels outside (including roof), plastic-faced hardboard (inside panels and cieiling panels), ...lots of woodscrews... and staples! - plywood floor, plywood panels for wardrobe walls and bed/cupboard/seat panels, lots of plastic bits, steel (small) sink, bits of plastic hose, some copper pipes about 1...