I probably would look for a rebuilt from around Denver. Probably a rebuilder would even deliver up your way. Might even take your old trannie (expecially if it's working) as an exchange, which would save you the core charge. Rockauto shows a 46RE in the 96 model year.

You don't need another transfer case, btw. It's a separate unit and bolts on to 46RE transmissions (you remove the tailshaft and bolt the transfer case on in it's place, I believe.) And your transfer case should work just fine with the heavier duty trannie. While you have it all out, I'd have a trannie shop look over the transfer case and repair anything that might need it. Seals, etc.

I don't know how fiddley it is to put a transfer case onto a trannie--there are shims, I know. But a trannie shop should be able to do the job for not too much money.

 

all 3 transmissions use the same tailshaft for the T-case. The Btch is the output shaft. I think the easiest way to do it is to drop the transfercase, then take the tailhousing and output shaft, and swap those to the new transmission. That way all the shims can get re-used for that tailhousing.