I am familiar with Loy Butte Road (also known as Forest Road 525) north of Hwy 89A from a couple years ago. As long as the weather has been dry, and you drive reasonably slowly, you will not need a 4x4. The road is a periodically maintained gravel road. There are places where it is bare slick rock, and places where water washes over the road. It is often bumpy and washboard, but passable. If it is wet, the mud becomes very slippery and the washes can be impassible. We boondocked at GPS 34.868109, -111.903752 with a great view of the red rocks.