When to go: As with most other popular sailing destinations in New England, July and August are by far the busiest months. If you plan to visit during the high season, reserve a slip or mooring well in advance. Sailing in June or September promises a slower pace and fewer boats, and fog is less of a problem in fall.
Getting there: Access to Martha's Vineyard and Nantucket is straightforward. In both cases, it's best to head northeast up Vineyard Sound, which is well marked and the easiest approach. If you're headed to Nantucket, take Main Channel. Currents run swiftly and seas build fast on the many shoals in the area. Be sure to know where you are at all times. Some cruisers favor rounding Cuttyhunk, at the west end of the Elizabeth Islands, rather than tangling with the fierce currents of Woods Hole.
Anchorages: In Nantucket Harbor, the designated anchorage area is east of the mooring field. Boats are allowed to anchor between First Point and Second Point, and they may anchor for one night at Head of the Harbor. Longer stays there will cause local residents to complain to the harbormaster. At Martha's Vineyard, be aware that anchoring in Katama Bay is now prohibited. Anchorage at Edgartown is in the outer harbor. At Vineyard Haven, boats generally anchor north of the breakwater on both sides of the entrance channel. There's also good anchorage in well-protected Lagoon Pond.
Charts: NOAA charts 13218, 13229, 13233, 13237, 13238, 13241, and 13242 cover the islands and surrounding waters. Another excellent source is the waterproof charts in Block Island to Cape Cod (2nd edition) from Maptech.
Cruising guides and books: Titles include Exploring Martha's Vineyard by Bike, Foot, and Kayak by Lee Sinai, The Enduring Shore by Paul Schneider, Waterway Guide (Northern Edition), and A Cruising Guide to Narragansett Bay and the South Coast of Massachusetts by Lynda Morris Childress, Patrick Childress, and Tink Martin, which covers the islands as well.