Welcome to the forum. From the age of your coach you probably will need an RV salvage source for body parts I would expect. You can try this attached link for a listing of US based RV wreckers.
Note that when I clicked on the link, my browser warned of self signed security certificate, so I bypassed the warning and got to the site. I can't vouch for its accuracy or security, but hope it helps you find a source for what you need. Good luck.