When we here in 2006 we did the same drive from Scottsdale to Payson. I took a photo of some cacti from the car while driving. We planned to stop when we got a chance, but then suddenly there were no more cacti and we only had a few blurry photos from the car.
This time we scheduled a stop at Tonto National Forest. Alex didn't think it looked like a forest at all.
The landscape between Heber and Holbrook was very strange. The grass was almost white, and looked blue-ish through our tinted windows.
We stopped at this Gift shop selling Petrified Wood. We spent ages looking around.
We went out to the yard and picked ourselves some bits of petrified forest.