Resolved, with many thanks for all the helpful replies.
The inverter (or converter), mounted in the least convenient place imaginable under the stairs to the bathroom, did not have a visible breaker. It was screwed onto the camper floor in such a way that I could not see that it had two 40-amp fuses that had both blown.
Once those were replaced, I found two more fuses on the 12-v panel had blown. When all the power was up, the DVD/entertainment console didn't work. Removing that from the wall, there was a 15 amp fuse in the power line that had blown. A small fuse in the thermostat (multifunction a/c & heat) was also blown.
All systems are functioning as they should now. I can only imagine that a surge from the campground electrical system or lightning strike nearly did us in. Any other thoughts?
Again, my thanks to folks for being generous with their time to make such helpful suggestions. Day two of summer finished so much better than day one.