Warrpath4x4,
I like your methodical energy with this project.
Be sure to closely inspect the frame before you get too far in.
If the transmission has a non-sychro'd grannie 1st gear, it is probably a Chrysler New Process NP 435L (6.68/3.34/1.66/1.00/8.26R) Has a cast aluminum cover.
Also available in 1980 W-200's was the NP 435A (4.56/2.28/1.21/1.00/5.64R) also with a diecast aluminum cover. If you feel 1st gear is too tall for a grannie 1st gear, this may be the one you have.
The last thing is the winch placement. I've had a couple Warn 8274's, and they are a TALL winch. Cuts off air circulation, at freeway speeds on the front of my jeep. Too tall to fit on the rear of your truck without either placing it very low, below the bumper height, or having it higher and be in the way of your tailgate, assuming you're going to use a tailgate. One of the 8K or 9K low profile winches would work better on the rear. I've a buddie that uses a 9K winch on the front bumper and a very low profile 6K winch on the rear and he can still use his tailgate. He's run the wheels off both of them when we're out wheeling. There are certain situations where he was the only one that could get to a good position to re-right a roll over or a recover a good stick.
Keep on keepin' on.
regards, as always, jefe