回复：回复：老羊兄还在吗？您老再给他指点指点

1. Old faithful area,
2. Norris
3. Mammoth hot springs
4. Grand Prismatic Spring
I think it's all. Search this site for more posts.
For Yellowstone, I think people should also drive around the entire 8-shape road inside the park and surrounding area.

One more piece of suggestion, you really should leave one day free time for each major place when you are planning, so when you get there, if you see something astonishing, you can have extra time to enjoy.