I'm glad that I did replace it but what a can of worms to open. It was my first time at the subfloor. i'm a fairly handy guy but one may say I'm not precise so it took me longer cause I went slow.
If you can only do the one section, I would just do it if you know your floor is in good shape. As I took mine a part I found more and more cracks in the fiberglass floor which rotted the whole floor and most of the cabinets. Another spot to check is behind the fridge
. The upper fridge
vent is very poorly designed and allows waters to run down the inside wall and rot the floor (at least in my trailer it did)
What I did was take a circular saw and cut the flooring 2-4" from the edge of the trailer, setting the blade just high enough that it didn't cut the fiberglass under neath. In some of the corners I had to use a Jigsaw but I would probably go out and multi tool saw that you can cut the corners where the saw could reach.
I also cut 12-18" squares in the plywood sub floor so it was easier to pry up.
It was a lot easier and cleaner to fix the fiberglass from the inside instead from the bottom of the trailer
A tip I could give you is when you do the floor cut back the sub floor so the joint is over where the frame is for more support. when I did the whole floor it didn't always line up with the frame, so I did a lap joint