You asked for suggestions on activities when you get there. I cannot suggest anything other than what will present itself, but when you leave there, I can suggest an activity that my wife and I enjoyed almost as much as the tour of the Grand Canyon itself, and that was the drive Hwy 64 along the road that goes east toward Cameron.
The canyon goes for several miles through Indian reservations, and some of the scenery is as beautiful as you will see at the canyon itself.
There are many places to walk right up to the edge, and no crowds to contend with.