.................After getting under this car, I have also noticed it has holes in the rockers,, rear frame (by the bumper brackets and leaf spring mount areas), in the frame rails behind the front tires, and the body door gaps change when you jack it up from one end or the other! I am sure this is due to the floor and frame holes. The only part that can be easily patched and is soild, is the trunk floor. This makes me question if I shouldn't go Gasser, straight front axle, or gut the floors, and do the Pro Street new frame, V-8, etc. route? Lol.
It would be a phenomenal amount of fabrication to repair the damage you describe for an "original" restoration. I combined (mostly/partly) a fairly solid "donor" car with my project in an attempt to save as much as possible of my first car. Not something I would recommend for a newly acquired project.
In retrospect........if one was interested in doing a full restoration project.......... you'd be far better off financially to buy a rust free body from Duane Hayes, restore that and swap parts from the project over to that as they were restored.
If you want an Aero with a modern undercarriage, that's been done quite well by others and it eliminates all the quirky Aero restoration/maintenance issues.