Seeking ideas for a five-hour loop trip out of Charleston SC

[wanderer2575]

I'm taking a cruise vacation in a couple months.  One of the ports of call is Charleston SC, and I'm thinking I might rent a car and take a short road trip out of the city to drive some different roads and get some sign photos (especially state shield assemblies).  I'm guessing I will comfortably have five to six hours for a round trip out and back to the car rental place near the port.  Any suggestions of a loop route in this timeframe where I can get a nice ride and some good photos?