SailorGuides.com:
A Trailer Boat Cruising Guide to Charleston, SC
Campgrounds and Motels
One of the great advantages of vacationing with a trailerable boat is that, once you've experienced all the sailing, fishing, and gunkholing that the Charleston area has to offer, you can unhitch your boat at a local campground or motel and drive your tow vehicle to all the inland attractions you'd like to see. Personally, I'm old enough that, after spending three or four days on my boat's bunk, I'm aching to stretch out in a real bed again, so I usually head to a motel for the landside half of my trip. Those younger (or just more nimble) than myself may prefer to save a little money and stay aboard their boat at a campground. Either way, Charleston offers no shortage of options for both.
The most convenient motel I found was the Days Inn off the #203 exit of I-26 north of town. Their rates were competitive and they have a large gravel lot in the back for parking trucks and trailers. The staff was very helpful and had no problem with me leaving my boat unhitched in the back for my three day stay (lots of motels have parking spaces for trailers, but not all of them are willing to let you store your boat there longer than overnight).
A few miles west of the Charleston Peninsula, the Oak Plantation Campground is the closest campground to Charleston. Oak Plantation offers over 250 campsites in a park-like setting complete with a private lake that is stocked with fish (no license required to fish here). In addition to modern rest rooms, wireless internet service is available at all sites.
Nearby, in the town of Ladson, is the Charleston KOA campground. The campground features standard campsites or, if you'd prefer a bed, you can rent a rustic cabin (bedding is not supplied and there are no private bathroom facilities). They also provide free wireless internet.
Just a bit farther to the west is the 32-acre Lake Aire RV Park & Campground. They feature a new playground area and swimming pool in addition to a private lake. In addition to free wireless internet, each site features a picnic table and fire ring.
The James Island County Park also features a campground with pull-thru and back-in sites. In addition to the standard amenities, the park offers a $10 shuttle service to the historic district visitor's center for those who would like to avoid the hassle of driving downtown altogether. A back-in site costs over $40 for non-residents, making this park the most expensive campground option, but it is also one of the most convenient.

