My last camper was a AF 1140 (now travel 5th wheel) --- things don't get much heavier --- my solution to adding a little height : sandwich 1 inch closed cell foam 4X8 sheet between sheet of 3/4 marine plywood and pickup bed (bolted through to be fixed) --- killed two birds with one stone, added height without worrying about crushing/tearing foam and added insulation which kept floor warm to bare feet --- PS: if me and DW were not 72 and needing more creature features ( such as couch and bigger shower space) I would still have my AF