So problem solving here guys....let's assume The walls are thin and either the inside or outside wal is going to get damaged.
-Why not maintain the integrity of the outer shell and frame and gut from the inside by removing the inside walls
- strip the foam back as far as you can
- increase the wall thickness slightly for added insulation
- install new interior walls
It will be a few $$ but considering the costs, still got to be cheaper than buying a unit of this size. Might help to make friends with a welder if you don't know one already
Gonna take some sweat equity and time, but almost everything we love doing here takes time and effort - 14 day dry cures and 12+ hr smokes.
Half the fun is the satisfaction of completing the task.
Don't lose heart. Good luck.