Isolated or the Freedom of the Open Road
The only stretch where you might feel isolated is between Flagstaff and Page as US-89 passes through the Navajo Reservation, and even there Cameron offers basic gas/food options. Note that Phoenix to Flag is all Interstate. If you will be returning to Phoenix, then I would heartily recommend that you take a different route back, just for the variety. And you can't get any different than returning via I-15/US-93 through Las Vegas.
AzBuck
A visual of the Moki Dugway and Goosenecks.
In my previous post I mentioned the Moki Dugway and Goosenecks SP, here are a few photo's from our trip to give you a better idea of what to expect.
It's all 2 lane black top Highway until you reach the Moki. First warning sign.
https://www.roadtripamerica.com/blog.../u.s.a-377.jpg
You can pull up at the top and admire the views.
https://www.roadtripamerica.com/blog....s.a-382-1.jpg
Then head down.
https://www.roadtripamerica.com/blog....s.a-385-1.jpg
https://www.roadtripamerica.com/blog.../u.s.a-386.jpg
An option to take a short detour to Goosenecks SP with Monument valley in the background.
https://www.roadtripamerica.com/blog.../u.s.a-396.jpg
Dave