Wow, we have a trip planned and are going west to east just off of I10 in Arizona. Most of our must see sites are a bit off the highway.In Texas Big Bend National Park is suppose to be awesome. In New Mexico, a side trip to Carlsbad Caverns is a must, and Silver City and the Gila Cliff Dwellings on the west side of the State.
In Arizona a side trip to Tombstone might be fun, and for a taste of the desert life, check out Saguaro National Park or Organ Pipe National Monument. Sedona is awesome but again would be away from I 10.
If your going to take 10 into California, Joshua Tree is interesting There is a campground on the southern end called Cottonwood, but most of the attractions are inside the park about 25 miles. 10 goes thru Palm Springs and that is a nice place to explore and learn about the sex life of a date. LOL