There are direct flights to Charleston from NYC (Westchester, JFK or LGA), Washington D.C. and Los Angeles. Breeze airlines has direct flights from Westchester + LAX! From there, you can either take Uber/Lyft which is about a 20 minute ride. The welcome party and ceremony will all be downtown so no need for a rental car unless you want one!
House Or Rental
Charleston has a ton of great rental house options Downtown and the city is very walkable. If you'd like to stay at the beach I would recommend Sullivans Island and Isle of Palms (about a 20 minute drive).
While we don't have a hotel block here are a bunch of recommended hotels to stay at if you want to go that route. Hotel Bennett Post House Inn (Sullivan's Island) The Charleston Place Hotel The Dewberry Zero George Mills House