Jumbo Rocks is a central campground in Joshua tree so you are pretty close to most main attractions. Skull Rock is actually in the campground. You can’t reserve a spot at Jumbo Rocks like most campgrounds at Joshua tree so I suggest arriving early to find a spot. The camp sites are fairly close together but that is to be expected in most campgrounds in National parks based on my experience. I would recommend finding a nice spot on top of one of the campground’s notorious jumbo Rocks to watch the sunset. Joshua tree sunsets are magical.