You can fly into Providence, Boston or Hartford... whichever is cheapest. Its about an hour from each, and unless you want to take a bus, its pretty much in the middle of no where. I know they have bus service to all major cities in the area though, so you might want to call them. Maybe do a websearch. I see the Foxwoods bus here at North Station in Boston most every day. No clue on cost, although I wouldnt imagine its too expensive.

If you cant get a room at Foxwoods, you will definitely need a car since the closest motel is a 10 minute drive or so.