[PDW HOTRODS]

I would do it with the cab bolted to the frame. I would have the doors on and adjusted before the rear corners. Then you can check door gap before you weld. The front corners tac weld and test fit front fender with doors on. If you don't test fit you might have to cut and move and make more work. The front fender lower rear mount should be held in a little to allow room to shim and adjust the fender.