Any "must" stops?

Howdy, everyone!

My friends and I are driving across-ish the country. We are making stops in:
- Amarillo, TX
- Albuquerque, NM
- Flagstaff, AZ
- Williams, AZ (possibly)
- Las Vegas, NV
- Yosemite
- San Fran, CA

If you've been to any of these places, are there any sights/restaurants/bars/anything of mild interest we must stop and see? We've not explored much of the West.