There are half a dozen marinas
in and around Charleston. You will be able to get to all of them except Ashley Marina (I think they're turning this into a dockominium) where there's a bridge about 55' high. Be ready for a shock when it comes to cost! Charleston Harbour at Patriot's Point and City Marina on the Ashley River would be your best bet. There are a couple of yards around but not many DIY yards. I am not familiar with the yards. If you're staying on the boat you can anchor
just off the City Marina or take a mooring
ball (City Marina again). It's kind of cold to be heading up to Charleston in January. Other possibilities might be in Beaufort
, SC. if you're set on SC. Prices might be a bit better. Of course, Charleston's nicer if cost isn't a consideration.