The Cobble Mountain Petroglyphs is a site near Gila Bend, Arizona that we haven't visited yet. To get there drive north from Gila Bend on the Old Highway 80. Turn left onto the East Indian Road. After 1.2 miles turn right onto North 307th Avenue. In another 2 miles turn right onto the Indian Road and take the first left after about a tenth of a mile. From there it is another 1.7 miles to the first site. We aren't sure how close a person can drive to the site before having to park and begin hiking but you should be able to get within a mile.
Included with this post is the GPS file and map that we plan to use for our first visit. If you don't want to wait for us to get around to it feel free to try the GPS file and map for yourself. With no guarantee, of course, but they most often prove valuable for us.