Maybe find a Craiglist handyman? That has resources, and assets available to help, and a shop? Or a metal building for cover, since winter is approaching?
A long shot I know, but finding a competent carpenter with the resources to do the job at his property might be easier than finding a RV shop that wants to take it on.
A few years ago, I followed along on a web site by a 30ish handyman who redid his Class A roof that had extensive water damage. During a winter in Florida. In his spare time. He'd rented a building so he could work out of the rain. Installed a new EPDM roof after repairing all the decking that needed it. So I know there are still skilled people in the world. Just sometimes it's hard to find them.
Good luck. Post pictures so we can follow along with the work.