If I had to pick just for a day trip, which would it be? Also, should I take my rental car on the ferry or leave it behind?

Martha's Vineyard and leave your car in Woods Hole. At this point, the summer is booked up for taking a car on the ferry.

Carol- the ferry is very expensive for a day trip and as native says - reservations are required and hard to get at this point. You can get the ferry from Woods Hole and leave your car on the mainland for about $6.00 per day.

I'd recommend Nantucket for a day trip - the ferry ride is longer about 2.5 hours but the island is smaller and therefore easier to see. It's a lovely island with a wonderful history, nice shops and beautiful captains homes and gardens. Bicycles are a good way to get around but they also have tour vans.

NANTUCKET!!!! Marthas Vineyard also nice but if you can only do one this is what I would suggest. You can rent a moped or bikes and leave the town and find some of the most beautiful scenery you will ever see. Make sure to take a swimsuit as there are alot of "off the beaten path" beaches. Have lunch at the restaruant at the marina in town. I sure do miss that area this time of year.I know reside in sunny Florida and really enjoy it in thae winter but still miss New England this time of year. Good Luck Have some clam chowder fo me!!

Please go to Martha's Vineyard.

please go to nantucket.

In all seriousness, I'd prefer the vineyard for a week, and nantucket for a day trip.