We stayed at Joshua Tree for three days in April 2017. The Blackrock campground provides easy access to the most interesting portion of the park, in my opinion. We stayed in site #45 and it was very nice, located on the side of a hill (slight) and close to a couple of trails. The iconic trees dot the campground. There is water available but no hookups. Cost was a very reasonable $20 a night. We also reserved in advance.