We recommend staying on Folly Beach in an Airbnb or Hotel near Center Street. That way you are walking distance to the welcome party, restaurants, and other main attractions.
There will be transportation from Folly Beach to Downtown on Friday night for the rehearsal dinner. As well as to the ceremony Saturday night. The ceremony is about 1 mile from center street.
Uber and Lyft are available on Folly to get to Downtown Charleston, Charleston Airport ETC, but wait times might vary depending on time of day.