I have been making some progress, I started off with the floor since I needed the flange that the inner cab corner welds to and I have always thought it makes the most sense to put things back together in the exact opposite as I take them apart. I saved some good floor chunks from my old cab and since the corner of the floor has a groove in it I needed to make the first patch with a piece of that and some flat sheet I had laying around.
I also made a small patch out of the same chunk of old cab to fill the bottom of the firewall and continue the stock body groove. I used a piece of flat sheet hand bent to fit in the inner portion of the cab below the air vent.
These patches went in without much hassle.
-Joel