Find Spare Parts for old Class C

check craigs list, here in tucson a guy has a couple he is wanting to sell. One door looks like it is from a clb winnebago

You probably already know this, but if the only thing wrong with the door is the screening itself, that can be easily replaced using the same tools and techniques as normal house window screens (spline tool and so forth). On second thought perhaps "easily" isn't exactly the right word, but much more readily and economically than sourcing and installing a replacement door.

Also check and see if somebody can fabricate one. They are not the toughest thing in the world to fabricate.

I have a few. I need length and width and whether the corners are square or radius corners

Try these people

Colaw