a suggestion for next cab: do any metal replacement with the cab properly mounted on frame, with fenders and doors in place [even if not always bolted] - after each area is repaired one piece at a time, refit everything before attacking the next area .... sounds like you wound up with an accumulation of minor misfits .... if you repair the steps, corners and pillars carefully with the cab on the frame, there should be no need to cross brace the openings even when the
cab is removed, except [maybe] when removing a major part of the floor
Bill