From the Mesa area, locate US 60--the Superstition Freeway--and take exit 191 to South Ellsworth Road. Follow Ellsworth north, and it will eventually become Usery Pass Road. Usery Pass interstects with the Bush Highway north of the edge of "civilization" and at that fork in the road you can make your decision as to where to go. The whole area is now a part of the Tonto National Forest--don't expect to see many trees, though.
The whole area up here is rife with little places for camping; sad to say, the Tonto National Forest web site needs a little work to make it usable, but here are links to some information on some of the more popular camping areas:
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Photo: A little hideaway in the Tonto National Forest by R&T DeMaris