Camping allowed, need $35 parking pass for each vehicle. No running water.
It's been years since I have checked, but there used to be a spigot at the rest stop in the middle of the freeway. Rv camping is allowed in buttercup, but you'll need a dunes pass. These are available at the ranger station on weekends or off-site sellers (cheaper) any time. Check the imperial sand dunes website before you go.
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