Can't recommend Sedona enough. Great short hikes.
http://www.hikesedona.com/most-popular-hiking-trails/. Good food...if bike rentals, jeep tours... Good hotels. We've stayed here:
https://www.tripadvisor.com/Hotel_Re...a_Arizona.html . We've also stayed at the "Star" but that was just wierd...(they rented us the front desk/caretakers room!)
I've visit the Grand Canyon but only do a day trip. Can't get enough of the view. I've found the family couldn't take more than some hours there.
I'd try a side trip to Prescott and "Whiskey Row" or a night in a b&b. The Whiskey Off-Road race is April 27-29th so either avoid or go then! No in-betweens on this choice...crowds...
Do all this before May!!!!