There are a few ways to get to Monument Valley depending on what you want to see.
You could take Hwy 6/191 out of Provo to I-70 and 24/95 to Blanding, Utah, then 191 south to 163 to Monument.
You could also take Hwy 6/191 to I-70 to 191 south through Moab/Arches Nat'l Park & Canyonland N.P. to Blanding to 163 and Monument.
Another way is I-15 south from Salt Lake to 28 from Nephi to 24 and take in Capitol Reef Nat'l Park to 95 south to Blanding and 191/163 to Monument.
We've done all of them and they're all good for RVs. Have a good trip!
Full-Timed for 16 Years
.... Back in S&B Again
Traveled 8 yr in a 40' 2004 Newmar Dutch Star Motorhome
& 8 yr in a 33' Travel Supreme 5th Wheel