This coach was bought used and the major issue was a large bubble behind the rear window.
When the skin is delaminated like this, it means water had gotten in.
The water had compromised all the luan wood used in the wall assembly.
We removed the bad wood and smoothed the rest.
We also had the rusted framing to deal with.
It was pretty rough looking.
Rust.
So we removed as much rust as we could and smoothed out the insualtion.