I ended up driving to Sand Wash after my first site about an hour west was kind of flooded and crowded. I showed up right when the sun was setting and was able to catch some horses about 20 mins after driving past the entrance to the area. The roads were very sketchy at some points, but by 2014 RAV4 was able to make it (though I did bottom out one time and came very close several others - at least AWD and high clearance are a must). Make sure you go to Sand Wash Basin's website. People that live there published an unofficial map of the different parts of the park with way more detail than Google Maps ever could, plus other facts and info about the place. The only downfall was it was super duper windy at night to the point where it was tough to sleep even with my heavy canvas tent walls. I ended up leaving the next morning because the wind had gotten worse and the forecast said it would be twice as bad as the next night. Definitely keeping this spot on my favorites list.