Floor Repair 1967 Caravel

[bpaolini]

I need some advice on how to repair the floor of my 67 Caravel. After gutting the bathroom area I've found some rotted wood under the sink area and also a couple inches of soft wood at the very rear of the trailer under the shower pan. I believe this was caused by rain water entering the rear of the trailer by the bumper as I'm sure it's not coming from above. When I jump on the bumper there is absolutely no movement between the frame and body. My question is can I repair the floor by just piecing in a small section of plywood with epoxy under the sink and using a wood hardener like the one from Dr. Rot on the soft spots? Since the body and frame are solid I was hoping I didn't have to get into major repairs or removing the covers from underneath the trailer. Any help is appreciated.