I would second the recommendation of Charleston.
James Island County Park is very nice and they have the best
Holiday Festival of Lights drive we have ever experienced and we have seen more than a few. However staying at James County Park Campground will be hard to reserve at this late date. I would recommend
Oak Plantation Campground where we spent Christmas a couple of years ago and had a great time. Don't tarry as they fill up as well. You can still see the Holiday Festival of Lights drive with out staying at James Island but it will require a little patience for the drive as it is extremely popular.