Martinsr, I see your point about using the 3 interior panels and it makes sense especially when you have the 5 window donor cab. In my case I am hoping the get the parts shipped in from out of state. And I think that I can do a good job of joining the panels either while the center panel is still in the truck or I will take it out then spot weld all three together.
Since I do my own welding, my plan for the outside frame piece is to weld some tabs on the back side of each frame to help hold them in place then MIG weld the frame in using butt welds. Then grind and bondo the surface. If all goes well this could be easier than replacing the whole cab.
