The high point of the Arrastra Mountain Wilderness is a surprisingly easy target, save that last 100', which we were unable to manage. Pretty tough drive required high clearance 4WD. Start hiking along an old road toward the obvious high point in the region until the road reaches the Arrastra ridgeline, at which point you hang a right and head right on up. The off-trail route is obvious and the terrain is excellent, with no serious impediments until very near the peak, at which point, narrow routes, and severe underbrush become an untenable problem. Don't get me wrong, the peak is attainable if you're motivated enough to plant your flag, but we just weren't interested in killing an hour or two for that last 100' elevation. Close enough I say!
Return to the road then keep heading west if you crave a more robust hike. Not sure the road will get you all the way to the Big Sandy, but it appears to continue into the wilderness for at least three more miles.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.
To hike From the Phoenix area, drive to Wickenburg, then NW up SR 93 for some 50 miles, or five miles past the Hwy 97 turnoff to Bagdad. Turn left*, then through an unlocked gate and drive five miles to the trailhead at 34° 25.119' -113° 21.572'.
* unnamed, looks like there is a call box on the apron