I would've recommended going through Sedona as well as The Village of Oak Creek, if you've never been since you'll already be in AZ, but sadly the overwhelming numbers of tourists in recent years have created such traffic gridlock within Sedona that many say it almost ruins the trip. There's also a huge wildfire just to the north which won't be out for probably weeks to come & has shut down the state road 89 going north to Flagstaff. But SR 179, which runs south of Sedona proper, is still open south of the main downtown area of Sedona that has the majority of shops & restaurants.
The big draw for many over & above the shops & restaurants of Sedona, is the majestic red rock scenery which is in full effect to the south of Sedona proper in the Village of Oak Creek. There's one main road, SR 179, that runs north up into Sedona proper, that's often not as congested on the weekdays until you get just to the Sedona business district. The red rock views are just as plentiful as the veiws within Sedona & they run along 179 as well as east & west for miles. 179 can be accessed coming off of interstate 1-17, which is the main AZ artery running from Phoenix up to Flagstaff. There are many places to stay & eat in the Village of Oak Creek so going up into Sedona is really not necessary.
Many claim that the red rock scenery of the area is as impressive as that of the Grand Canyon (I agree) & you can actually walk or hike out among it whereas you can't experience with the Grand Canyon scenery unless you take a tour or get a permit to go down into the Canyon. As with the Canyon, I feel all should experience the red rocks of the Sedona area at least once in life, there's really nothing comparable to it in the world, just as is the case with the Grand Canyon. Getting to Oak Creek would entail going south from the Grand Canyon on 1-80 to Flagstaff, then south on I-17 to the Village of Oak Creek exit, then back north through it on 179. From Flagstaff on I-17 to 179 takes about 2 hours or so & the forested scenery along I-17 is a treat as well.
An alternative trip instead of Oak Creek to consider would be going south from the Canyon down to Flagstaff to pick up 89, then north into Utah to visit Zion or Bryce Canyon national parks. This is all assuming that you'd be visiting the South Rim of the Grand Canyon. If you'd be going to the North Rim of the Grand Canyon, then going into Utah is much quicker & going down to Oak Creek would be a much longer trip. Regardless, enjoy your trip!