As a minimum, I would change the oil and filter, and drain out any old gas left in the tank.
Need to do a whole lot more than just drain it. After a period of time some of it hardens and won't drain out. When you put fresh gas on it some of it "melts" and mixes with the fresh gas. When you shut the engine off the old gas hardens again on the intake valve stems, as the fresh gas evaporates, and can stick them shut. If the truck was sitting with gas in the tank all those years the only safe option is to pull and clean or replace it.
