Well, I worked in that country for 12 years and drove just about every paved road and maybe 20% of the dirt roads.
It is all open range. Read: watch for 4 legged critters grazing on the right of way.
Be aware that the local population generally considers 45 mph to be top speed, so..... Keep your eyeballs peeled and don't run 80 mph on a dirt road.
Also, the pavement is hilly and the dirt roads even more so. All of the blacktop is in good condition, drove a 2 WD Ford Ranger pickup one winter there with no problems. Rest of the time, I had 4x4's, either pickups or RAMchargers (yeah!! 3 of them!)
If you have a 2x4, stay out of the sandy areas. It can be a long walk back.
Warning signs are often placed too close to the dips to be effective at high speeds. Can't tell you how many times that Ford Ranger pickup scraped the bottom on plain surface blacktop. Was carrying about 1500# loads then. Too much for that truck, but oh well... .
Canyon de Chelly is an awesome place to visit, as is Monument Valley. No matter how many times you go there, it is always different. The colors change by the hour. Mornings are oh, so beautiful and the evening sunlight turns everything red.
Cloudy days bring out the grays and coal streaks, bring a big memory card for the cameras and download it everyday to your laptop.
Or, be prepared to spend a chunk of bucks on celluloid.
Chinlee is a mixture of old and modern. Hogans right beside framed modern homes. The highschool is of the latest architecture (1990's). Window Rock is unique, but still a mix of old/new. Window Rock BTW is the capital as it were of the Navajo nation.
John