All comments based on Verizon service. From SOBO perspective.
About 5 miles south of pine you walk along some power lines. Cell Reception (CR) there.
Once you've gained about 1500 feet coming up off the Verde, you will have CR as you hike the cut up to the ridge (you can tell because you're still able to face back to Payson).
There is reception at the Barnhardt/MDT trail junction.
I did not have reception again until I was about 5 miles out from Snowflake, where I was in open view of Mt. Ord, which blasts about amazing CR to the surrounding area. Basically, you should have reception every day to 1.5 days depending on your speed.
In Passage 25, strongly consider a stay at Polk Spring - it's an Eden with beautiful water.