Humphreys Peak is beyond gorgeous! Make sure to bring plenty of water and snacks, and don't forget hiking boots!
If you're looking to camp here, stay at Freidlein (spelling??) prairie! It's free and right on the mountain. There are tons of pre-arranged areas to camp, so it is first come-first serve.
Stopped here with my mom on our way to back to Phoenix and wow! Super tasty food and a great atmosphere. We found it a little hard to find at first, but well worth the few times we had to circle around to finally notice it.