
Let me try this with linked pictures.
SOOOO I spent a little time planning and researching after the deconstruction of the CV (Thanks guys!) Meanwhile, the frame was sitting in the shop patiently waiting

I kind of neglected taking pictures for a while. I'm doing this by myself, so documentation is often a hindsight.
After another hitch at work (and more online reading), I came home and started working on the truck again. I took the floor and firewall out of the CV since I plan on using the CV a/c and everything else. Sorry, no documentation of this process. Since the floor in the 66 was in need of repair any way, it made the floor and firewall swap a no-brainer to me. I cut out the floor and firewall of the 66, and began fitting the cab onto the floor and firewall of the CV while the CV floor and fw were bolted onto the CV frame.

So I rolled it back into the shop like that (minus fenders) when I went back to work. While at work, I did some more reading and planning. I worked a 35 day hitch and only had 3 days off before I went back to work, so I didn't get much work done to the truck. After that hitch I had some time off ( a little too much).
So, I started welding up the cab to the floor of the CV. There was a gap between the sides of the cab and the floor of the CV that tapered from 5" at the door to 2" at the top of the firewall. I made a few patch panels from the CV for the floor, and fabricated the patch panels to joint the cab to the floor. I got a little crafty and repurposed an old Ford tractor hood to transition the newly formed step down at the door.
Back Wall

Rear floor and back wall patch

Floorboard patch

Fender well area of the firewall

The newly created step down with a little help from a tractor

I patched up the rear wall that I clearanced for fitment.

These are all the pictures I have at this time, but I have made more progess. I spent the last 2 days fitting the front clip to the CV frame. I have everything cut and moved I will have to rebuild the core support and move the radiator and A/C condenser back nearly 2". Before I can do anything to the core support, I am going to sand blast the front clip that I pulled off the rust bucket. Once I blast and prime, I will completely rebuild the core support and mount it to the CV frame. While I'm blasting, I might as well blast the bed as well. I will get back on it next week if I am not at work.