The original floors are only ¼" plywood glued to styrofoam. You can carefully peel up the bad plywood and lay down a nice ⅝" plywood floor. Two sheets will do the floor near the door,bath, hall in front of sink/stove/refrig, and the rest of the floor from there to the front wall to both camper sides. I didn't replace the styrofoam, just glued in place with spray foam ....which glues glues the foam great. Use exterior underlayment .... sealed/painted on all sides and edges before installing. Leave a small gap at the walls or the floor will squeak. For the seams I used Bondo as it dies hard and fast, better than wood filler.
As for the beds ..... the support is to the metal frame of the bunks and the plywood-styrofoam panel is just the bed. I found a You-tube about them. Mine were OK, but I wanted to see how they were made.
Our 2005 is so nice now, it seems better than new. I may even replace the tenting this spring so they look as nice as the rest.
Hope this helps. Ray