I stayed at the Mt. Pleasant KOA, north of Charleston on US 17. AFTER I missed it and drove across the bridge into downtown Charleston at rush hour in my 'C', pulling a toad 4 down. No place to turn around without backing up. I was scarred for life. Charleston is much easier to see from a toad. The KOA was far enough off of US 17 to be quiet and peaceful with big spaces and mature trees, and next to a large lake.
For sure, visit Patriot's Point. The WWII aircraft carrier Saratoga is open for tours, as well as the USS Laffey, a WWII Destroyer, and the USS Clagamore, a WWII submarine. The Saratoga was a sister ship of the Lexington, that I served on in Pensacola. Different name, but it was the same layout. WWII ships are being converted into razor blades at an alarming rate.
Charleston is very proud of its Civil War era history with many ante bellum homes open for tours.