I spend a lot of time in Joshua Tree and I haven't found a site better than Indian Cove for getting away from the crowds. Lots of hidden sites in this campground and loads of climbing and tortoises. You can even hike up Gunsight Canyon and come out on Boy Scout Trail in the park. There is a secret underground maze that only the rangers and experienced guides know about. Please don't try and find it without one of those people! Lots of people get lost in the beautiful rocks trying to find their way around.