...here's a crazy idea: ferget the aluminum exterior, and clad a new build with adhesived TPO (just tarp the "old girl" outside as you strip out the good stuff, while you build in the barn near-by)....eventually, as time/money allows, aluminize the exterior (spray spar varnish on all wood surfaces and end-cuts before TPOing)...this is pretty out of the box, but I've always had ths idea kicking around.
Just be aware that the post 2011 TPO product (the patent ran out in ~~2011) are extremely diverse (in quality); so investigate the myriad brands carefully.
