Great trip. Been on some of those roads a number of times. The desert is a lot more awesome at 3am than it is at 3pm in the summer. It is extremely hot. .It took about 6 hours to drive from N Arizona to Palm Springs. There were no resource. It was a few more hours to LA. By comparison, the trip from S. AZ into Southern California south of SanDiego is much faster. Even then the desert in S.AZ and C.CA are brutal hot in the summer, but not quite so warm in January. .
The only time the desert air is somewhat cool is well after 12 am mid-night and before 6am. Denny's at Winslow, AZ has amazing food and service.