Plenty.
The food. Get ready for half of your budget to be good restaurants. They all compete, so you’ll get great choices anywhere.
With that said, towards the end of E Bay Street, check out Pearlz, Ru Ru, and Blind Tiger Pub. Brown Dog Deli for their sandwiches and Off-Track for phenomenal ice cream are great as well. Sweetwater Cafe for breakfast/brunch after walking Market Street in the morning. Circe’s Grotto for their sandwiches. Vincent Chico’s for Italian. Pour Taproom for top floor beers.
The two things I recommend for food in Charleston is walk everywhere; you’ll burn a lot of calories. And avoid Hyman’s. Their seafood is pretty good, but it’s cramped and over-commercialized.
For activities, go to Folly Beach for a day. Plenty of eye-candy, but it’s really a nice beach. Some good restaurants right near the beach. If you’re driving there, parking sucks. If you’re going to Uber there, pre-schedule your rides, especially from Folly Beach. You’ll see less drivers go down there to pick up sandy people.
Do a ghost tour. They’re fun. Do a boat tour. They’re okay.
I should have more, but I’m drawing a blank on some of them.