I hope you've started some in-depth water source planning. Desert crossings can be challenging/dangerous in summer. Consider night riding.
I know a little about the AZ portion. Some of it is on reservation land, where secret, or "stealth" as we call it, camping is not allowed or advised. You may be able to get permission if you ask. It's certainly feasible on US BLM and FS land which abounds along your route. There are huge fenced ranch tracts where you might have problems camping.
The lower elevations north of Flagstaff where you cross the Colorado and Little Colorado may be unbearably hot this month. The same may be true in parts of Utah, Nevada, and CA at the lower elevations.
I also know a little about the OR portion. If you haven't been to Crater Lake, take this opportunity to modify the route and see it. Though the McKenzie Pass crossing of the Cascades is a good one, too. It's hard to go wrong in Oregon, with some of the best bike touring in the US.