pongo: the guys are right about the floor. Its not worth the hassle to cut the edge and try do it from the inside. It would be less headache to raise the body.
You mentioned refinishing what you have. Thats a good idea and especially if the bottom is in good shape. I plan on filling a couple places in my floor and putting a 1/4" overlay on top of the original to make sure its nice and smooth. Maybe put a little liquid nail around the edges....just a thought.
