Hard to find a non-touristy site this time of year, what with all the Midwesterners flocking here But since the best times are sunrise and sunset, there will be fewer at those times. Suggest you check out the Superstition Mountains- there's a county park, lots of trails and scenery there, can make you feel like you're away from the crowds. Out that way is the Goldfield Ghost Town, touristy at times, but if you get there early, there are few around. Also touristy, but you can find isolation for a few moments, would be the Desert Botanical Gardens, nearby Papago Park. South Mountain Park is very large, lots of trails, rock art, etc. If you're willing to drive about 2 hours, the Vulture Mine in Wickenburg is a great place, lots to see, so doesn't feel crowded. Lots of other places around, but this is "the season"- arrive early or stay for sunset to avoid the crowds.
Save some time for a great exhibit at the Phoenix Art Museum of Brett Weston and Sonya Noskowiak (museum closed Mon&Tue). Photomark, near 22nd and McDowell is probably largest camera store in town (they have used analog stuff, but pricing not that great); there's also Tempe Camera. If you need film processed, ColorMark, next to Photomark does good work.
Have a good time!