My uncle lives in Charleston and I always go to visit him in October or November because I love the Ghost Tours there. The Ghost Tour I like the most starts at Waterfront Park and takes you around the city telling you about the ghosts of Charleston's history.
The guides also talk about the haunted places and what happened there. It's kind of superstitious but it's a lot of fun to do for Halloween. It's also really affordable, so I go with a bunch of friends and we have an awesome time!
The Charleston Aquarium is nice but I have seen much bigger ones elsewhere, but little kids would like it.
Battery park is also nice. I like climbing the Oak trees there and collecting oyster shells because there are so many!