[Riveted1]

Thanks again for your help, AZDon. After you told me about the drier being missing, I went and looked at pics of several burbs and trucks on e-bay with AC (don't know why I didn't think to go there before!) I only found one that had the large drier next to the evap box. All of the others had a small drier mounted above the compressor. That's when I realized that I forgot to mention (and take a pic) that the PO put a newer-style drier out on the front of the core support next to the condenser.

There is one service fitting on the POA "update kit" (the switch/fitting coming out of the evap box) and it looks like the other one is on the backside of the compressor. The switch in the POA kit is supposed to cycle the compressor on and off.

So I guess my first plan of attack would be to get all of the correct lines and then proceed from there.