Not really a lot of progress but here's where it stands. The cab is still on saw horses in the middle of the shop. After I cut out the back of the cab I sliced out the rear section of the floor. Just used some 1" square tube to replace the inner structure. Doesn't need to be fancy because it's all hidden. Then I tacked in the ends of the patch panel.
The problem was that the patch matched the profile of the floor but the back of the cab bowed out and overlapped about an inch.
I decided that the least invasive strategy was to do a tummy tuck. The vertical cuts will be hidden on the inside by factory braces. The blue tape is the top of the bed.
Muuuch better now. I ground down most of my embarrassing welds and moved to the firewall. I filled all of the unnecessary holes left from the old heater that I won't be reinstalling, the remote oil filter from when it had a flathead almost 30 years ago, and various other features that I'm going to delete.
The other thing I whittled away at was the bottom of the bed. I needed to notch and clearance for the rear swaybar and chassis crossmembers that interfered with existing real estate.
I also won't need the factory fill hole at the lower rear of the driver's side. I was going to let the body guy deal with it until I noticed that the lower cab has almost the same profile. I think I'm going to use the piece I cut off to make a patch and fill it.
I bought a Upol Raptor bedliner kit to shoot the underside of the cab and bed before they get mounted. The hiccup now is that I need to haul it 450 miles (each way) down to my brother to get the firewall finished and painted before I permanently mount it to the frame. Not sure if I can convince him to shoot the inside of the cab too but it kinda makes sense.
As far as the chassis goes, it's done aside from some brake lines. Hoping to have it mobile by next summer. Planning to test fit everything and drive it a little before blowing it apart again for final body and paint.