Re: West of LV, East of LA
If you are interested in camping in the Mojave, note that there are tons of spots on BLM land.
If you want the campground experience, I'd recommend Owl Canyon just north of Barstow. It's kind of like a little Red Rock Canyon (which, like many state parks, is falling apart and ridiculously expensive) with lots of fun hiking and fossils. Ramadas in the campground, and firepits. Another nice campground is Afton Canyon, which is one the river, so gets interesting wildlife when it's quiet.
A nice area near the preserve is down by the Granite Mountains; there's a dirt road off the pavement and I think the spot is called Granite Cove or something. It's open camping; basically the Preserve lets you camp anywhere that has been historically used as a campsite, and the rangers say that means if there's a fire ring there you're OK.
The visitor center at the Preserve is awesome; one of the Park Service's best and I'm usually not a fan of the NPS. The old railway depot is great, and it has a fun little café inside. Make sure to check out the old maps in their reading room; they're easy to miss but very informative.
If you are a bit adventurous and have a high tolerance for political incorrectness, the OHV areas around those parts have some good exploring. The Mojave Road, of course, but there are also some other interesting spots. Rasor Road I find particularly interesting, but you probably don't want to be in there on a weekend.
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