The gap between door and fender looks awfully tight! That is the major cause of catching a door.
If you can't find a better door, that looks reasonably repairable to me. I would remove the door and put it on a stand. Then, make a template of the fender's curve to match your door up as you hammer and dolly it. Rough it in, get the curve right, then cut out the bottom rotten part. Make a template for that area out of cardboard and then transfer to metal. Make your bends over a rounded corner to mimick the soft bends of the original.
Good luck - post picks!
