If you like science and history, consider stopping at the Cosmosphere in Hutchinson, KS, on the way back. It's amazing. They have a great collection of rockets. German, US, and Soviet. They have the Apollo 13 Command Module.
On the way out, you'll be in BBQ heaven as you pass through Oklahoma. Consider Burn Co. or Albert G's in Tulsa. A local twist is slow smoked bologna. It's surprisingly good.
Zion National Park in Utah is on the way back. It's beautiful.

If you've never ridden out west in the summer; hydration is critical. Enjoy the trip.