I doubt the 91 Ranger regulators will directly fit into a 84-1988 B2. Check RockAuto or LMC truck. The wiring harness for the power windows goes left to right across the radiator, you have to remove all that to properly do the swap, and of course the door harnesses, and switches. Do a continuity test on the harness that goes in front of the radiator. I have fixed a few RBV where the short to control the passenger side was in that harness, and the switches and door harnesses were good on both doors.
The OEM Ford motors will probably work from the 1991, I have put FSB window motors into RBV when the dealership did not have the Ranger ones in stock and the only real difference was the harness length.
If you have a center console, you can put two momentary two way switches (get ones that use a round hole) in that and do not bother running the bulky harness to each door and just run the two wires along with your speaker wires. If you have no wires at all to the doors in a proper harness, you might find using Aerostar side door type switches cleaner, though obviously they will not work when the door is open. Which might be a hassle in an accident. I would suggest a self resetting relay (lower then the fuse) to power the windows along with the fuse. I think the last ones I bought were from e-trailer.