I drove to Sacramento and visited with my sister for about an hour, and then before leaving Sacramento, called Lisa to let her know I was on the last lap, so to speak, and to bring her up to speed on the van issues. When I mentioned the AC and cruise-control issues, she said, "Sounds like you have a vacuum leak." Both of those systems on my van are vacuum operated. In retrospect, we speculate that a hose was not completely reattached (we're hoping this is the cause of the service-engine light) and that eventually the hose came off completely. If so, and assuming we can find the missing connection tomorrow, the engine-light problem may go away and we can concentrate on Plan A (using the Astro to go to Spokane/Portland/Seaside).
Although my original plan was to drive straight home with no more stops, my bladder had other ideas, and I did stop at Donner Summit. There were rain showers in the Sierra (hooray) and while there's no snow at Donner, there's what looks to me like some new snow on some of the higher Sierra peaks that wasn't there when I went west, thanks to the recent storms. Keep 'em coming, I say. The van restarted without too much trouble at Donner and I made it home without incident.
Good think tomorrow is a holiday; looks like we'll need it to work on my van.