Swap cabs... but I would drive the drivable truck and fix the other if it's only going to take a year or two to fix the 5 window. You'll basciaaly be tearing the entire truck body apart to swap cabs. And you may get into more work then expected. Before tearing the drivable one apart take the 5 window apart first just incase there are surprizes..... Enjoy the 3 window now and work on the 5. Once ready then you can swap.
