I highly recommend taking I-15 up to St. George, then taking 9 thru Zion NP. If time allows, drop south then thru Fredonia down to Jacob Lake, and hit the north rim of the Grand Canyon. If you can't then just hit UT 12, but if you go to the North rim, head back north to UT 12, one of the best roads in the nation. Red Canyon SP, Bryce Canyon, Escalante Canyon, Capitol Reef NP... the hits just keep on coming. When you get to Henryville, turn south on 95 and run the White Canyon (kinda boring the first 20 miles or so, but then gets pretty). From there, you're in the Four Corners area. You can jump up to Cortez and catch Mesa Verde, then over thru Durango and east on 160. You can then drop south at Pagosa Springs down thru Chama and catch 64 east.
Whichever route you take, try to exit the mountains east of Taos on US. 64 thru Cimmaron Canyon. If you drop any further south, you're back on I-40. But you're pretty much screwed any way after Cimarron Canyon, as you start across the plains...but you can hang on 64-412 east thru Tulsa, then get into some good twisties back in the Ozarks across northern Ark.