More Yellowstone stuff for my sister
If you can go to Bechler, do. It's really out of the way, because you can either hike in, or drive in from Idaho. Daddy was born while Grandma and Grandpa lived in Bechler. I need to scan in the photos I have of Grandma and Grandpa when they lived in Yellowstone. Bechler is a nice waterfall part of Yellowstone.
I like Norris geyser basin. It's not by the rest of the basins, but it's different. It's usually not so very crowded, especially if you get away from the parking lot.
Since you think the neat geyser book is too expensive, try this geyser website. They're working on getting photos and descriptions of the geysers there. Pictures are useful when you're trying to figure out what you're looking at.
Midway Geyser Basin isn't terribly exciting, but it does have two huge things- Excelsior Geyser and Grand Prismatic Spring. GP is huge (the largest hot spring in the western hemisphere, I think) and beautiful, although you can only see it well on really warm days, and Excelsior is just huge. It's dormant now, but it's had some huge eruptions. But if you just drive by Midway Geyser Basin, I wouldn't be scandalized.
Upper Geyser Basin is huge-o. I'll do that later.
One fun thing you can do, although I've never done it, is find out at the OF Visitor Center if there are any backcountry ranger hikes while you're there. They can take you to neat places that are hard to find. There are lots of really interesting places that don't have trails.