If you pull the motor and trans etc. you can do a bang up job of repainting the frame. If the shop you take it too is familiar with C/K Chevy's I would pull the nose, doors, and bed. Pull the motor, trans, fuel tank, etc. If you have access to a compressor needle scale, and Chassis saver the frame. Or sand blast it, prime and paint it? Run new brake / fuel lines etc. Reason I say if they are familiar with them is they won't have a problem reassembling it with someone else taking it apart. Or you could pull the entire nose off in one piece. Might make there job easier if they tear down the front clip.
If you are reusing the doors you could take the mirrors, door locks, and handles out etc.Then when it comes back from paint you could put them back in.