Well after all the postings I have made here the past couple months, my van is finally road worthy. The transmission is working properly even though it still feels a little harsh from 1st to 2nd, everything else is smooth as butter.
What finally ended up fixing it was a chassis ground. I was on the right track, I knew about this one being bad, but I kept overlooking it. It was the chassis ground right next to the radiator on the battery side. Somehow the piece broke loose which caused the bolt to move about an 1/8" every direction. Once I got all the wiring disconnected from that bolt, I ended up ripping out the chassis ground bolt which left a hole the size of a quarter. Wasn't any way to fix it without a welder, so I started looking for a different ground. Found a nut welded to the chassis next to the driver side headlight. Put a bolt through it, connected all the wires, and tightened down using lock washes and the double nut method.
All the gauges work well, van is changing gears all the time, and it feels like a whole new van. I also ended up getting a new alternator (105amp) right before I moved the chassis ground. Now I'm positive the old alternator might actually be good and will be looking at going dual alternator here soon. I also did a partial big 3 upgrade. 1/0 from the alternator + to the battery +.
So all in all, it's been a big headache, but I am very happy to have a great running 1995 Astro with 150K miles on it.