I wanted to share how I was able to rescue the rotted out lower hinge area in my 65 Monza. I made the mistake of storing my project in a shed with a dirt floor. The tin worms had a feast. The first time a poked a screwdriver through the lower door hinge mount my heart sank. It was really bad. Then I remembered what Jackie Howerton said about metal work; if you're really skilled, you can fab big pieces. If you're not so skilled, you have to fab smaller pieces.
Since I'm not so skilled, that's what I did. I figured out where the rot ended in the hinge area, drilled indexing holes to locate the piece, and cut it out. I used crude wood hammer forms to make shapes that I could handle and replaced rotted areas one by one. I fitted the rebuilt piece using the index holes and finished welding. Then welded the piece in where I cut out the spot welds. I have yet to mount the door, but i have no doubt that it will fit. The process was tedious, but not too difficult. The photos tell the story.