After a day of cutting, bending, and welding, the front floor pan and front cab support actually fit correctly. The driverside front floor pan stamping had quite a few flaws. If you look in the pictures, you'll see that I still need to trim the lower edge of the pan where it meets the rocker panel, as that edge is completely wrong. Both parts are screwed/bolted in place and ready to be welded up as soon as I get back to it in a couple weeks (going camping next weekend).
Using the old copper trick to weld up and redrill a hole that was slightly off.
Had to move the body mount bolt hole as well.
We stuck the door back on the cab just to verify that nothing has moved before the floor pan gets welded in place.