Zions National Park, Bryce Canyon National Park, Capital Reef National Park, Arches National Park, Canyonlands National Park. All in southern Utah, all colorful and different. All with a days drive of each other.
If you want to take a few extra turns in the road, the north rim of the Grand Canyon and Monument Valley in Northern Arizona or Mesa Verde in southern Colorado.
Las Vegas is about 3.5 hours south from Zions, fun to see once, if you like bright lights and lots of folks.
Lots of other great places in other western States, they're all spectacular too. Most of the southern Utah locations are desert type canyons with lots of red rim rock country. Not so much in lakes and rivers like areas to the north.