[Excerpt] Each leg of a trip to "Chappy," as residents know it, begins with a formidable bottleneck. First you must get to Cape Cod through the gantlet of traffic on U.S. Route 6 between the interstate highways and the Bourne Bridge. Then there is the regulated ferry service to Martha's Vineyard, which requires late winter reservations for summer season car transport, thus limiting the volume of cars allowed on the main island.