You can open carry anywhere that is not identified in Arizona law.
http://www.packing.org/state/arizona/
Prohibitons on carrying firearms in these venues apply to both open and concealed carry.
Any establishment licensed to serve alcohol for on-premises consumption (e.g., a bar or restaurant, but not a liquor store or supermarket that sells alcoholic beverages in sealed containers).
Any establishment or event open to the public where the operator makes a reasonable request for you to give them custody or remove the weapon from the premises. A sign would qualify for such request. By law, cities and counties are required to offer on-site storage if they ban weapons but not all are in compliance.
The grounds of any public school, other than the parking lot. In order to be legal in the parking lot the weapon must be unloaded, and, if left in an unattended vehicle, such vehicle must be locked and the weapon out of sight.
State universities and community colleges. Community-college parking lots are treated like those of public schools.
Commercial nuclear or hydroelectric generating stations.
Polling places on election day.
Correctional facilities (this includes the parking lot of such facilities).
Game refuges (except during an authorized hunt).