Hi Buckeye,
At campgrounds that are open in freezing weather, this is usually handled by the campground by way of heat tape, or an enclosure, or both. The heat tape is often plugged into the 20amp receptacle on the power pedestal. Or they shut off the water when temps drop below freezing. If they don't protect the exposed plumbing, or shut the water off, they could have freeze damage.
I suppose if you're visiting the exceptional campground that leaves the water on without heat tape, you could bring your own tape, wrap it around the riser and faucet, and tape it tight to the pipe and faucet.