You can do the walk in either the north or south direction, and it's pretty easy to catch a boat out and arrange for another to pick you up at the other end a few days later. The typical northern starting point is Ramsey Bay, on the north-east coast of the island. The ferry from Cardwell actually approaches this beach from the western side - a network of mangrove lined estuaries run almost all the way across the island, and a landing at the end of one of them leaves you with only a few hundred metres of boardwalk to reach the east coast.