In Chinle, the Best Western Canyon de Chelly inn is located at the mouth of the canyon. Good rooms and the food very good (if on the menu, try the Arizona spring lamb). Parking area for motorhomes, and board for your horse.
If you want to see the canyon, half day to day trips may be arranged here, but if you want a guided jeep trip, arrange ahead of time on the internet.
The drive north, to Mexican Water, is a grerat scenic route.

When the Navajo finally got back to this area, after being herded to Ft. Stanton by that bigot, Kit Carson, and U. S. troops, one of the places that they restored their fields and orchards was Canyon de Chelly (more properly Canyon de Tschay, var. spellings). The soil at the bottom of the canyon holds water just below the surface throughout the year. The altitude is about 6000 feet, so the dry heat never seems oppressive.

Holbrook, as pdq recommends, is a prime center to explore the area, but it is about 100 miles from Chinle over State and Navajo Nation roads (roads not bad). Each of these areas requires a day for a quick look-see, but more is much better.

Window Rock (it does have a very photogenic natural bridge), on the eastern boundary of AZ, is a good place to start exploration of the eastern Navajo nation and some of the old trading posts, including the Hubbell Trading Post, 40 miles west, still run in the old way by the national parks, with reasonable prices for blankets, silver and other handcrafts.
The old Toadlena Trading Post had a display of very unusual pictorial weavings the last time I was there; the area is a center for Two Grey Hills weaving. Many of the best weavers, however, sell to the better dealers in Sedona, Santa Fe, and other centers; not depending on the casual tourist.