1972 Amerigo Camper Rebuild

All kidding aside, I'm having a ball with this thing. I guess I need to name her, because she's the only date I've had in a while. I spent the better part of the afternoon with her today. The P.O (wish I could find appropriate words to go with those)has just added layers to cover damage instead of repairing the damage and fixing the leaks. There is an extra 1/2" floor over the original that has had two different layers of vinyl flooring laid over top. I'm having to scrape that off to get at the screws so that I can take it up. I may need to get it out of the way before I can remove the shower. Bought a Dremel Multi Max to use to cut the screws holding the rafter/joists to the top 2X6 band. I'm afraid that if I try the sawzall, I'll cut the fiberglass top. This thing seems to work just fine, and can't reach all the way through. I'm thinking of cutting 2X4s with an arc to replace the rafters to make them thicker in the middle and replacing the roof plywood with 3/8, so that I can walk around up there. Any thoughts on that? I know that the more I add the more weight I have to pack around, but I'm willing to sacrafice a little here and there. BTW congrats on your purchase Rog.