Charleston, SC where to stay and things to do?

DW and I have stayed at the local KOA, Nice Park easy to navigate, very helpful staff. Relatively close to the "Tourist" attractions as well. Good Luck and Happy Camping !!

We like James Island County Park campground. It may be difficult to impossible to get a reservation there if you're trying to go in the next three months, though.

Our favorite thing to do in Charleston is to just go to the historic district and wonder around, eat at different restaurants, etc. One of the carriage tours is nice to help familiarize yourself with the area. With teenagers along you might consider Patriot's Point, a visit to one of the plantations or a drive out to one of the area beaches (Isle of Palms or Foley Beach).

Maybe a tour of Fort Sumter, There are numerous tours of the city, A haunted Jail tour, and maybe a sailing trip on the water to watch a sunset over the city, or a paddlewheeler dinner and music cruise. Day trips to Congaree National Park, Savannah (see the cemetary).and do try a "Low country boil" while you are there.
Myrtle Beach is a little touristy for my taste but there are many tourist venues there as well and a giant sky wheel you may enjoy.

It would help us with recommendations if we knew what your interests were. Herself and I like to visit churches and historic sites as well as mountains; we also go to some music festivals.

Charleston's Cathedral of St. John the Baptist is beautiful. We also enjoyed the Gateway Walk. It's not well known but it's a shady walk through some of old Charleston history complete with old cemeteries. You can get a map to it from the Charleston Visitor's Center.

For places to stay I've found using Allstays.com has been very reliable and up to date. The feedback on the places is helpful too.