I believe she ditched it off the beaten path too. The reason I'm not feeling it about Elephant Mountain/Spur Cross area is that it would be out of her way. She would have to double back to town, then on the highway out of town.
I haven't been up that way in years, but from what I remember it's a dirt road in and out, once you're out of Cave Creek.
If you look on Google Earth for the area between Wickenburg and Kingman it is desert, mountains, mines, and not much else. There are dirt roads that would be easy to go back a mile or two and not be seen. Then, back on the highway (hwy 93) towards her destination
I'm not saying "no way Jose'" she didn't go there there to ditch it. It's just that there are more opportunities along her route to Kingman. Which would take a lot less effort on her part. Also, it's nighttime and June. It would have been hot and dark. MOO