Sedona

I wouldn't imagine more than 3-4 hours. It's about a 2 hour drive up to Sedona from Scottsdale then at least 3 hours to the Grand Canyon. The main street in Sedona isn't that long so unless the bus does some driving around the area that should be enough time to see it all.

Agree with Buzz48. There's not much in Sedona itself aside from tacky souvenir shops and overpriced food. Take time to go down the History Walk and read the plaques. You'll learn about the history of the area and be surprised at the movies that were filmed in the area. I knew about Monument Valley but never realized how many well known films were made in the Sedona area! If you have the stamina to come back up again, continue to Tlaquepaque which is a Mexican style courtyard with small shops and cottonwood trees providing a break from the sun.