Most of the bison we saw on the first day, were bulls walking down the side or middle of the road (they got to choose which). One walked right by Steve, and he got a good shot of his nose. On the second day, we got a good look at a lot of bison, who are gathering for the fall rut.
What a great time! We took two days to see the whole park, but collected all the Passport Stamps at the Visitors Centers (there are 6). We saw Old Faithful erupt, and even cooler, saw Beehive Geyser erupt. Old Faithful is on a 90 minute cycle this year, but Beehive is on a 16 hour cycle, so is harder to see.
Had a great time, but didn't get to see everything there is to see. Probably would need 3 or 4 days to get to all of the trails and stops.