Here are a couple of things that many times get overlooked when traveling NE Arizona.
Antelope Canyon: a few miles east of Page, AZ. Probably the easiest way to hike and explore a beautiful "slot canyon". Owned and managed by the Navajo, they will charge you but it's worth it if you've never been in a slot canyon. There are upper and lower canyon areas with different pricing and physical requirements.
Canyon DeChelly National Monument: Near Chinle, AZ. Campground at entrance station. Drive your own vehicle around the north and south arms of the canyon or explore the canyon itself with a Navajo guide. This is a very scenic National Monument more interesting than Monument Valley.
Have a great trip.