We've stayed at the Meeting Street Inn (downtown Charleston), and couldn't have been more satisfied... it was very enjoyable and we didn't want to leave... highly recommend:
Meeting Street Inn in Charleston, South Carolina | B&B Rental
More choices here:
40 Charleston, SC Inns, Hotels and Romantic B&Bs
Don't know of any out in the countryside that would fit your request, but it might be worth checking with the Charleston Chamber of Commerce to see if they have some recommendations.