In Arizonathere are the most rewarding to visit Side Trips. I mention here only the most important, there are countless more trips possible.
The Grand Canyon is just a stone-cast away, as Sedona, Monument Valley, which is already partially in Utah and requires a more circuitous route.

You can also visit Prescott it would be worthwhile to get there. Highway 89A it is an extremely beautiful Highway, on the hills and the small gold mining town of Jerome.

Other side trip would be possible to Lake Powell, where you get to see the Horseshoe Bend of the Colorado River and Glen Canyon Dam. In addition, to visit the famous Antelope Canyon in Page.

Further east is the Canyon de Chelly a worthwhile goal.

For all the goals you have set aside at least an extra week.