Hi Tony, We took a vacation this summer to Charleston, and used AirBNB to rent a house. We were looking to hit the beach while also being able to cruise around Goose Creek to give our son Spencer a view of the local town. Plus this gave him some Fun memories of the area to help him during the tough times.
The house we rented was about 30 min from the base...and was fantastic. I recommend the owner of the house and here is some info regarding the rental. While there may be some houses closer, at least I can vouch for this one: 1234 Secessionville Rd, Charleston, SC 29412
I will let others respond to the questions of liberty.
Thanks and good luck! (tell your sailor we said Thank You for his service!)