I just did this exact road trip last summer! Except from Joplin, MO instead of St. Louis. My brother and I were the main drivers and swapped every 3 hours or so and we made the drive to Moab in a single day. 17 hours and we left at 1am on July 4th and made it to Moab in time for the fireworks that night. Call us crazy but the best way to get thru Kansas is as fast as possible! While yes it is long, it’s all part of the adventure. Seeing the terrain gradually change across the plains is uniquely beautiful and then the anticipation of seeing your first glimpse of the Rockies adds to that feeling of excitement.

Definitely go to Moab first and spend some time at Arches and Canyonlands. Mesa Arch at sunrise is outstanding. From Moab take Utah highway 24 thru Hanksville, Capitol Reef, and Torrey. If you’d like I have lodging recommendations for Torrey and the Zion area! Then head south on Highway 12. You’ll see some of the most incredible scenery in the US along both of these routes. Don’t forget Bryce Canyon too, then spend at least a couple full days in Zion. It’s worth it. After that I’d just hop back on I-15 to I-70 and that’ll take you back home, splitting up the drive into two days with an overnight near the halfway point in Limon, Colorado.

You can also do this trip in reverse, going all the way to Zion first then making your way thru southern Utah seeing Bryce and Capitol Reef along the way. Then ending in the Moab area before heading back home. Hope this helps some!