This weekend I am going to try and bolt the cab on the frame to properly test fit the doors, rocker, and fenders at the same time.
I was looking at the pics of the cab corners (it's late and I'm tired - not going out to look at the actual cab corners) and was wondering if the gap problem with the door could be solved by taking a piece of wood and gently banging out the B Pillar where the cab corner is spot welded to it.
EDIT: Wondering if I can bang out this part from the inside to match the shape of the door.