Questions about floor repair

[RIBoater]

I have soft spots in my floor on both sides of my center tank. When I did the tank I also noticed that the foam was water logged under some of the floor. I'm hoping you guys can let me know if my plan sounds like it will work.

I'm planning to cut around the edges of the floor close (1" ???) from where the floor meets the side panels, pull out the floor skin, replace the foam, repair/replace the underlayment, put the skin back on, fill the seams, fair it and paint the whole thing.

My questions are:
1. Am I missing anything?
2. If I don't cut too deeply will the skin come up without the plywood that's under it?
3. Will I have to support the edges if I cut that close to the edge?
4. Do I have to glass the new underlayment before putting the skin back and what should I use (AC / BC plywood) for the underlay?
5. Am I out of my mind for even thinking about this? I could probably cut out the soft spots and rig/patch something but if I'm gonna do it I'd like to do it right if it's reasonable to do.

I know I'm asking a lot here but thanks so much for your help.

Paul K
RIBoater

Oh yeah - pics are on their way