i always take 93 from PHX to LAS and back, and there's a lot of those memorial highway markers (where people commemorate loved ones who died in accidents on the road). traffic is spread out but very fast. it would be a great road if there were NO CARS, but i would be leery unless i had support vehicles riding with me (like in the RAAM).

i hope you can get a good route, but like pedal wench said the rest stops are few. its very sparce country. miles and miles and miles and miles of nothing but joshua trees.