Very Cool!
When I had to swap the frame on my ' 63, I jacked up the frame and cab as a unit, then built an A-Frame through the open windows, unbolted the frame, and swapped out the tires/rims for a set of bare times. I then lowered the frame down on to the rims and rolled it out from under the cab.
That way I could swap out the running gear and roll the new frame under the cab, lift it and bolt it to the cab. Remove the A-Frame and put the original times/rims back on. That made the swap very easy.
From the pictures you posted, it looks like that process might work for you.
