I actually already cut back the roof half way across, and also the wall down to the chair rail. Once the roof is well sealed I'm going to use a screw jack to lift up the rafters enough to give access to the top plate to repair it and then sister on some joist boards. Hoping it is a quick and easy repair, and would be even better if I am under budget. Side note, I checked and all I can get from local supplier is bright or painted sheets, no vinyl coated. Do you think it would be worth using a few rattle cans worth of paint on the inside?