As stated above, lots of "if this, then" stuff to tie all together. If running U-joints for the front drive shaft, then setting the front yoke at the same angle as the output on the transfer case is what you want to do. That will give you a 6° to 7° positive front caster angle on an open knuckle Dana 60. You didn't state what axle you are putting in, I was just guessing.
If you are running a CV front drive shaft, then the yoke is supposed to point directly at the transfer case output yoke. That will probably take you down to 2° or 3° caster. That low of a caster will make the truck very lively on the road and the steering will be slow to self center coming out of turns. However, you can fine tune it with tire pressure so it will be a good ride. Unique, but still good.