a loaded question, there being many placer deposits in AZ. never been much of a drywashing fan,but that's me....
I've heard many good things about Arivaca from people who live there and prospect. south west central, not too close to any major city.
if you prefer more greener pastures (so to speak), the Bradshaws are good, Prescott is my favorite small city in AZ, the only downside is that winter there is, well, winter.
there is always the old standby of Quartzsite and vicinity, lot of club claims you can work...but...for me, way too crowded with cheezheads and other assorted icebelt nitwits with rv's.
the Kingman area isn't as crowded, land is dirt cheap (literally) in places nearby like Golden Valley and Yucca and there's gold to be found.
just a few thoughts, others will weigh in.
I love AZ, all the good w/out the SoCal attitude.