There are organized tours of the Battery area along the waterfront, or can do it yourself.  Has some great architecture for homes that were only meant for summer use in the 1800's, while the owners lived in plantation homes back on their farms the rest of the year.  People live in most of the Battery homes now, so can't get inside, but the Nathaniel Russell House is a museum and open for tours.
https://www.historiccharleston.org/Russell.aspx

Maybe a client would be willing to join you on an organized culinary tour: https://charlestonculinarytours.com/

I've stayed downtown but the hotel is forgotten, it's the surroundings that made memories.