You can reserve spots online. I'm pretty sure they close the sights for about a month In the winter.
I'd be amazed if there wasn't. See other answers about water.
Yes open all winter electric only water at restroom and dump station
It's not all that busy there. It's kind of a hidden gem. You should have no problem getting in there in January.
Yes there should be a spot , but it doesn't hurt to call and ask
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