First thing to look at for the crooked cab is the front cab mount metal. They are prone to rust out and cause the cab to collapse. The rear cab mounts are shackles to allow movement when the frame flexes on uneven roads. Without these type of rear cab mounts, the cab metal would become damaged on uneven roads. The rear shackles have rubber cores in them which are replaceable.
I can just about guarantee that the hinges need to be rebuilt. There is a hole in them which allows for oiling them. Most of them have ever been oiled since they came off the assembly line. Once the hinge pins wear out from lack of lube, the door will sag and the latch will bang on the striker, causing damage to both of them.
