Re: Sourcing filon & roof corner/gutter - please help

https://www.grainger.com/category/raw-materials/aluminum
https://rvstoredirect.com/collections/awning-drip-rails
https://www.rvpartsnation.com/exterior/rv-fiberglass-siding/arctic-white-rv-fiberglass-filon-siding/

If I may inquire a little more info. You are planning on gutting the camper of walls, ceiling, cabover and slide out while leaving the interior intact to rebuild the rest from scratch. What about the floor?

Or are you planning on removing the filon and patching the frame where needed and replacing the filon over it? Either way, big job!