We stay at Old Mill Stream Campground. This year they have decided to close from January to April 1st. If you are going in the next few weeks before the end of the month they will be open and have sites with heated water spigots. Call for reservations - oddly they do fill even at this time of the year. I am not sure what else may be open there as this had been one of the few that remained open after October.
If you are going during the Spring or summer they are all nice, for the most part and all need reservations in advance as this is a very popular area. We do prefer Old Mill Stream Campground over the others. And the owners are incredibly nice and accommodating.