Yoy can go to reserveamerica.com to make reservations. The sites were very large,so I'm assuming so. I believe they label on their maps the hookups and site size. I don't know what their availability is.
When you reserve you pay for the whole stay. You can cancel with a full refund as long as it is within a certain time frame. I am not sure how busy it is, or if they are even open, in December.
Go to recreation.gov to see what sites are available. They don't charge a reservation fee like reserveamerica does.
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