For future reference, here is my two-day itinerary. Each day was 5-6 hours of driving, all I wanted to do.

Day 1: Drove from Bozeman to the north park entrance, Mammoth Hot Springs, Tower Falls, canyon drive, lower falls (missed the sign for upper falls), over to Norris but road to Norris Geyser Basin was closed, paint pots (didn't have the energy for the two-mile round trip walk to this sight so skipped it), out the west entrance. Spent the night in West Yellowstone.

Day 2: Drove through west entrance toward Old Faithful--Firehole Lake Drive, Fountain Paint Pot trail, Grand Prismatic Spring, Old Faithful, Old Faithful Inn. Arrived at Old Faithful five minutes before it erupted; didn't know predictions in advance but couldn't have timed it better. Drove back to Bozeman via 191N, and spent the night there.

I left hotels early, and traffic wasn't bad (almost none from Bozeman) until going back to Bozeman, when it was close to a parking lot for miles and no apparent reason. Both ways were easy drives. I wasn't near any restaurants at meal times, so glad I took food with me. I easily got a parking space at every stop.

Only two brief stops for animal crossings on day 1--a deer and a couple of bison. Although I didn't see much wildlife, this week was a good time to go before the crowds descend.