Fix minor slide floor rot with 12 inch Headlok screws

From the pictures, iy looks like you may have some wall sheathing damage going on, also. I'd suggest to cut the fabric back to that point where the luan board stops and remove the luan board. That will probably allow you to look up into that area and see what is good and not so good. When you replace everything, use an undercoating spray to patch up any areas without fabric.