A number of CTD owners have gone thru the same thing. You are not alone here bud... .
The single most used approach to fixing this has been to remove the door, and have a backing plate welded/brazed in. The plate was predrilled to allow for re-attachement of the hinge.
It's a tough one to do, because you need to remove the door and fab a piece to fit inside the door. Hopefully it's done before the hinge pulls thru the metal.
I recall another member, long ago, mentioned he made a wire stop strap, kinda like ones used on tailgates, to stop the door from overextending. I don't know how that worked out in the end, but it sounded like an option to consider.
bob.