There is certainly plenty to see in Utah. Monument Valley, Canyonlands, Arches National Park.to name a few. In Colorado, the mountains are gorgeous especially Rock Mountain National Park north of Denver.
Unfortunately, when you reach Kansas and start driving east, you will be facing about a thousand miles of flat monotonous farmlands. It can get pretty baring for anyone expecially children. Of course, West Texas does not offer much better.
If you are interested in music, Memphis and Nashville are great attractions.