Brand new Class C owner and RVer

Once I got it all ripped out I bought 1/2 inch foam, 1/2 inch plywood and contact glue. I cut the pieces of foam and glued them to the plastic base over the cab. I had to cut the 4/8 sheet of plywood in 4 pieces so I could get it in my car so I held the pieces together with repair pieces (metal squares with 4 holes, one at each corner). Then I screwed the wood through foam with 1 1/4 inch screws all around the sheet metal of the roof of what used to be the cab of the van. I still need to put on the fake wood laminate and staple down the wrap around so it looks good but it is solid and much better built than it was when it was new.