We just came in from a day of work on the H.H. Our floor was shot so taking it out was more a matter of sweeping up rot, pulling nails, sweeping rat crap, and figuring out how the thing was put together. Unlike other trailers we have worked on where the entire floor is built and finished, and the walls built on top of that floor the HH is different. The floor is independent of the walls. The whole system is different. Directly on top of the angle iron and channel iron frame is a flat aluminum "dust guard". Not like the A.S. belly pan that is below the frame. Then they rolled out fiberglass ins. and on top of that were some 1/12x11/2 sleepers about every 2'. They compressed the insulation where they landed but I guess it still gave some R value between. On top of that was the plywood flooring, 5/8 originally attached to the sleepers. This floor system DID NOT go to the edges, but was held back 11/2" from the edge, which was made up of a half dozen outriggers on each side. I believe the walls were built complete with their own bottom plate, framed and sided on the outside so they could lift the complete unit up onto the projecting outriggers. Then a long lag was used to draw the two parts together. At least that is my guess.
For reasons only a shrink would know, we aren't going to take the skin off or re-do the framed walls. We are going to fix what is there, in place.That means I need to reverse engineer a floor. The original frame was "lacking" in my opinion, so we welded in additional metal The old "dust guard" was a goner under the toilet, sink and water heater, so the last 4 feet of guard will be new. Then new sleepers, and new ply 4 feet at a time because the guard prevents access from below.
Years ago, the croupier at the craps table at Tahoe used to call out "hard ways work, play the hard ways" and I took that as a life lesson. Do it the hard way.