Going on a roadtrip from Dallas Texas to Washington state. Looking for some fun things to do along the way...?

Any ideas? We will be going through Amarillo Tx, Denvor CO, Cheyenne Wyoming, Rock springs, Salt lake city UT, Boise, And Through Yakima. Live in WA flying to TX to pick up a car and driving home. Any ideas of water parks. Anything that's outdoors. Shopping malls. Anything that is a need to see. For kids and adults... :) Thanks