AZ Cheap Eats

My 12 yr old and I are going on an Arizona adventure and looking for cheap eats. We're open to all kinds of cuisine, would love a fantastic, non-touristy Mexican place somewhere in the mix, and have no problem with dives but do not want chains (other than In-N-Out, which is East Coasters need to try at least once). We just need to keep meals relatively inexpensive. Here's where we are headed and what meals we'll need. Any and all suggestions are appreciated.

Day 1--Phoenix to Flagstaff, maybe by way of Sedona but trying to avoid driving on switchbacks. Will need lunch in Phoenix and dinner in/near Flagstaff.

Day 2--Flagstaff to Joseph City to Winslow back through Flagstaff ?? to Tusayan. Breakfast, lunch, and dinner. Thinking lunchtime pick up of takeout or grocery store run to cover dinner as I've heard Tusayan restaurants are mediocre at best.

Day 3--Tusayan to Williams to Prescott to Scottsdale. Will need breakfast, lunch, and dinner.

Day 4--Phoenix. Will need lunch and dinner.