I just returned from a trip that took me, in part, through the Navaho Reservation in New Mexico and Arizona. For those who are planning a similar route, I advise you to think long and hard about it. Although maps show towns at regular intervals, most of these towns are only a small collection of houses with no services; large towns and cities can be up to 100 miles apart with limited services between them.
On the other hand, this was some of the most amazing riding I've ever done. Much of the terrain is a constant series of mesas and the view from each mesa to the horizon is unbroken. This is true "Roadrunner" country, as spectacular as anything in the cartoon. Of course, this also means the at the road is a constant series of rollers as it dives down each ravine and climbs the other side. The tops of the mesas are not flat either, usually a series of gentle roller and false flats.
Riding through the Navaho Reservation is something that I'm glad that I did, but I'm in no hurry to repeat the trip. For stronger riders, it certainly could be a worthwhile trip. Just be aware of what you're in for when your map finger traces out a route through it.