"Looking at Yahoo Maps and based on my knowledge of the area this is my proposed route:
Highway 95 South (near Boulder City)
Highway 164 to Ivanpah Rd through Mojave National Preserve past the 40 to National Trails Highway. NTH to Amboy Rd. Amboy Rd. takes you to 29 Palms. Highway 62 goes through 29 Palms to the 10. Jog over to Indian Ave to Highway 111. 111 to tamarack Rd. It gets a little unclear here but some how you need to get to the Cabazon area. Then to Beaumont to San Timoteo Canyon Rd., which ends near Redlands and Loma Linda. From there there are tons of ways to get back to Fontucky."

Some of that is in my backyard as it were. 95 south out of Boulder is excellent with wide shoulders. 164 going west is ok with no shoulders, and gets worse out of Nipton. Preserve roads can be a bit harsh, and of course without much water. Nipton general store open regular business hours. Cima general store open 10:30 - 4:00. (Monday - Saturday) Kelso Depot Info Center should have water. Amoby ????
Just what I know of that part to help you out. I am used to the heat, (live in the Colorado River Valley) and I stay out of that part of the world from early June until Labor Day. The risk of anything going wrong without shade and water are not worth it