Depending on your location in the Phoenix Metro area it is possible to pick up the White Mountain Apache reservation also, just using a stock antenna on a handheld. In 1999 I spent two months in Scottsdale on some family business and put up a discone and it boomed in. I forgot to mention putting in the Prescott National Forest. One of their repeater sites is south of a place called Crown King at a lookout on that Forest, the name of which escapes me at the moment. That site booms into Phoenix also. The Tonto, Prescott, and Coronado Forests have the lowest elevations of the six National Forests in Arizona. That also reminds me that I've been able to hear the Coronado from Phoenix as well. Mt. Lemmon is their hub site and it comes in pretty fair in Phoenix, but I don't remember if that was on the discone.
If you beat me on the others I suggested you have probably done your research well. There are also some listings for the Indian Reservation that borders the east side of Scottsdale, but the name escapes me at the moment. They have a tribal police, a large shopping area, and a casino so it can be interesting. They have a federal government frequency up in the 172 MHz range for wildland fire as well.
The Arizona Department of Game and Fish has six or seven regional frequency pairs for repeaters, but I've never heard anything on them, however, the statewide frequency of 151.460 repeats traffic from all over the state. I find this very interesting myself due to my first career, which was with the U.S. Forest Service and included 4 years on the Kaibab National Forest west of Flagstaff. I worked with AGF and that agency as well as all the other natural resource agencies are my favorite listening.
You are going at what is often the best time of year there. I've been in some hot weather in April there, so when I lived in Flagstaff we used to have our 11th commandment, "Thou shall not go south of Camp Verde from April through October."
