Head up to Prescott for hiking/kayaking/getting out of the heat. Weather should be in the 80s/90s and dry (with possible afternoon monsoons). Great restaurants and shopping there too. You can also head off to Sedona from there, passing through the cool little town of Jerome. There is also Horseshoe bend (my avatar photo), and Lake Powell, if you have more time.
AZ is beautiful in summer, just carry water in your car, and avoid the more remote highways when its really hot (many parts of rural AZ don’t have cell coverage or roadside phones). Be safe.
edit: Oops, looks like I’m late to the party lol