Ron,
We have a 1987 Starcraft Starmaster. Although we haven't actually removed
the flooring yet in ours (next project!), we have removed cabinets, crawled
underneath, etc. enought to see that GENERALLY the cabinets are just
screwed/bolted to floor, floor is screwed/bolted to metal frame. We will
also be removing the "walls" at the bunkends (the slanted ones) because not
only do they need replacing, but they rest on the floor. I thought the walls
on the sides did also, but they don't appear to in ours.

Doesn't look like it's going to be that big of a problem to replace our
floors. A good piece of advice that we got was to seal the new floor either
with some waterproof deck sealer or with spray-on rubber sealer, top AND
bottom. Also to use the old floor (if we can remove it in one or two pieces)
as a template for the new floor. That way all the cut-outs and holes will be
in the right places.

Kathy in Houston, TX

I haven't, but I bookmarked this site in case I ever have to...

http://www.alinerclub.org/diy_piet_floor.htm