You may want to stop in Williams, AZ, off I-40 and take the steam train to the South rim of the Grand Canyon.
I second that train ride. . it is very good and worth the cash for 1st class. Had loads of fun. There is/was a RV campsite with in walking distacne of the station and close to the tracks, so you can get photos of the train coming back going out if you are there the day before... loads of fun and a good treat! PJ