Hotel
We have a special group rate for guests at the Marriott Town Center in downtown Charleston, within walking distance of plenty of restaurants, bars, and the river - you can get the group rate at the link below. If it fills up we also recommend the Embassy Suites or the Hampton Inn downtown.
Flight
Charleston has a (tiny!) airport! If you're in New York, there's a direct flight from Newark to Charleston on Breeze airlines.
Train
Charleston also has an Amtrak station! This is probably the easiest/cheapest way to get there if you're on the East Coast, although the train has been known to have delays.