I would make sure that the motor runs good enough that you would be confident to drive the truck. Then I'd make sure the clutch works and the truck will move under power. Then I would do a complete brake system rebuild. Once the truck, runs, moves and will stop then you need to check the lights, wiring systems. If you have money left at this point, buy some gas and put some miles on it.
Good Luck
Don
ps...cleaning the gas tank out should be part of getting it running good.
