Trans won't shift, no power to windows, A/C, etc

1994 Chevy Astro Van ext, 82,000 miles - I need some help on what to look for and check. The engine starts fine. No electrical power to the front windows, A/C compressor won't come on, no interior lights, speedometer doesn't work, and the transmission will not shift out of 1st gear. I do have turn signals, radio, and power to the front seat. This happened twice last week and today. The first 2 times I simply drove slowly for a short distance (less than 50 yards), put the van park, turned it off, then back on and everything worked alright. Except for today. Any ideas on what I need to check or replace? Just to mention, I replaced the battery a few days before all of this started to happen. Is there a relay somewhere I should be looking at? Thanks