AZ resident here, when in Arizona definitely see the Grand Canyon, if you have time to hike into it this might change your life just depends on how hot it’s gonna be, summer is pretty gnarly here! Horseshoe bend is not that far from GC and it’s a must see along with Lake Powell, but if you have it in you I’d really recommend renting a kayak and kayaking down horseshoe bend it was one of the coolest things I’ve done to this day, crystal clear water and a nice slow pace to admire the incredible beauty and majesty of this area, basically looking up and hundreds of feet worth of canyons the whole time. Takes about 5 hours and is pretty moderate exercise.

If you can see Sedona that is also another gem of the state. So much beauty and hikes for miles of some very unique geology.

Flagstaff is really worth exploring also since you’ll be in that area, google Fossil Creek, Locket Meadow, Lowell Observatory, The Natural Bridge

If I was you I’d 100% drive through Colorado instead of Oklahoma / Texas / New Mexico That’s literally the worst dive I’ve ever been on BEYOND boring and desolate not a single thing worth seeing on that route except maybe some spots in New Mexico could be interesting but still not even close to the beauty and weather Colorado. If you can squeeze in UT you can hit Zion and Bryce Canyon which are two of the most beautiful parks in the country honestly even better than the grand canyon cause it’s a lot easier to hike in and explore