Wow, I just spent an hour looking at your project. Great job on the detail.
Mine had pretty much all the same problems. After market body parts are a godsend, but still needed plenty of massaging to make them fit properly. The cowl and floor are now solid again. Since this is going to be a driver, I didn't go into as much detail as yours. I wish I had the patience to take pictures of the project along the way.
I noticed that you're from South Carolina. My truck came with South Carolina plates. I wonder if there any way of looking up the original owner?