If time allows, Fort Moultrie National Monument is a national park worth visiting. If you have a boat, Charleston Maritime Center is an excellent marina, and a great close by hotel is Wentworth Mansion. So much exciting stuff to do here at Colonial Lake, too great to be true. Head out on the scenic water at Harborage at Ashley Marina, and a day of fishing at Knot at Work Fishing Charters is always a great idea.
Colonial Lake is right next door to Devils Fork State Park which is a pretty site. It's always enjoyable to go for a fishing trip and a glorious location to do that is Charleston Inshore Fishing.