[Jasen]

I've got a 97 AWD cargo. Empty I average 19-20 mpg, but it's never empty anymore, so I'm at 14.5 mpg.

On the Astrosafari forum some have dropped the front drive line, but only reported a 1 maybe 2 mpg increase, their still turning all that gear in the front diff. The only way to truly dump the AWD is to swap to a 2wd sub frame.
The biggest gains we've seen in mpg is a V8 swap, probably 3-5 mpg increase.