I am driving form Chicago to San Diego, what attractions are there to see along the way?

We are taking our son on a driving trip across the northern US from Chicago to SD, Ca. We would love to see some amazing US sites. Mount Rushmore is our first destination, but then what? My 8 y.o would love to see dinosaurs, anything having to do with gems/mining, caves/caverns & national parks. Any suggestions would be great. Thank you