Check with the local chapters like Apache Junction, Scott 602 434-2843 or some of the other chapter in the Phoenix area.
Scan the hillsides nuggets will be deep in a sand wash and detector may not be able to reach them. Look for areas along washes also where there is runs off the hill side. Check decontaminated quartz out crops and below. Others may have some better information for you.  

 

One of the most informative things I have found is Jeff Williams youtube videos.  The guy acts nuts to some, and just funny to others, but he seems to really know his geology and works the daylights out of that desert in most of the different ways.  I think the learning curve on the desert and knowing what to look for is even higher then stream placer prospecting.  I try to watch at least one of Jeff's videos a day and watch them over and over hoping some of his knowledge is going to sink in, especially on the geology and where its good to run metal detection, or dry washing, or vacuuming.  He has videos on about everything and the cumulative desert geology information is quite extensive.  

This will be old news to this thread but for future reference.... two publications that belong in every prospector's , or would be prospector's, arsenal would be "Fists Full Of Gold", Chris Ralph and "Follow The Drywashers, A Nugget Shooter's Bible" Jim Straight. The first one has more gold related geology in one book than any I have ever seen. The other is a comprehensive guide to how and where to use a detector in the deserts of the southwest. I have the 3rd and 7th editions of the bible but I think it is now in the 8th printing.  ╦╦Ç