so whatcha wanna know john? i used to own one, and have driven several.

they are:
1. g.m.'s first and last attempt to make a "luxary" cabover by adding automotive features. it was lame attempt, and came late as the laws regarding overall length were about to change, which pretty much ended the era of the cabover.
2. dash is easy to read, guages are big and bright, but the dash was so low oncoming traffic could see the driver scratch his nu----well, the big winshield and low dash made visibility pretty good.
4. for a big guy who has to drive a long distance, the seat won't go back far enough. guaranteed backache.

5. air conditioning system has some lines that fit only the asteroid. if they break, and they do, whoever fixes them needs to know how to improvise. done right, the a/c could freeze you out, but not if you were parked facing the sun. "greenhouse effect".
6. many cab things are proprietary to g.m. and g.m. only. parts are scarce. as with all big trucks, what wears out on one, usually is worn out on another.

on the whole, the truck is fairly easy to work on. not many things are "hidden", but under the dash isn't a fun place to be to work on things. still, a person can. remember under the dash means you are not standing on the ground, or thefloor of the truck. adapt, and overcome is all i can say. not alot of "goodies" for the astro to dress them up from the factory. mostly chrome bumpers, big marker lights, and aluminum tanks, but remember g.m. was never into custom trucks, and they built them on the same assembly principle as their cars. (a mistake). they were good fleet trucks, but most owner operators didn't like the things as they were #1 a cabover, #2 were sorta plain, and #3 didn't feature many options aside from the drivtrain.

what else ya wanna know? i know where i few are sitting.