First natural stop would be at historic Cameron Trading Post for food, fuel and bathrooms. Maybe some shopping. Then, if you have 3-4 hours of remaining daylight, consider the detour through Wupatki/Sunset Crater NM. Only do this if you have sufficient time. You need to arrive in Sedona before sunset.
Or you can skip Wupatki and go on to the entrance to Sunset Crater. Good stop (especially if you have a NP pass) to use the restroom and stretch your legs. A good gas stop is the Safeway at Flagstaff mall.