Do you plan to drive as much of the original route that still exists; that is the original route as completed ~1926 or so (if my memory serves.) I believe that the original route was shortened sometime in the '30s in selected places. I know for sure that Oatman, Arizona was on the original alignment, but was bypassed several years later for a more direct and straighter route from Kingman to Needles. I also think that there were some changes around the Missouri-Kansas-Oklahoma alignment too, but I would have to research it.
The routing in California near Pasadena also changed a few times over the years as freeways were constructed. I think the original terminus was in downtown Los Angeles, but was extended to the Sta. Monica pier in the '40s.
Enjoy the journey!