Are you there just for the weekend? Figures it would be when I'm out of town in the other direction.
(I live about an hour inland but am going to a beer festival in Greenville). When do you leave?
There aren't really any "hidden gems" that I know about unfortunately. The Piggly Wiggly at Market Commons is probably the best source that I know of for bottles, growlers, etc., here's their Facebook page:
https://www.facebook.com/pages/Byrds-Beer-at-The-Pig/167739199945589
I'll inquire with some friends as to what the best drinking spots are, I know a few guys in the craft beer crowd that go down to the Beach regularly.