Depends a lot on where you're going, plus when you're going. New Haven, CT, to Charlotte, NC, is about 12 hours, though you could get stuck in lots of rush hour and/or beach traffic once you get south of Washington, D.C. Asheville, NC, would be a hour or so longer, plus you'd want to go down via I-81 rather than the much more congested I-95 corridor. If you're headed to the Outer Banks, it'll get a little slower as you get off the interstate, plus you might hit beach traffic in season.