If you take the trail to the top of Tavewa Island you are in for a treat. It has the best view of the Blue Lagoon (yes where the movie was filmed). You have a 360 degree view from the top and it only takes 15 mintues to get there and is well worth it.
The main ferry meets the local resorts boats out in the middle of the lagoon. Each resort has its own 18-20seat boat which they seemed to fit more people on. The first day i arrived the waves were big and crashing over the boat. 3 inches of water seperated us and the boat sinking.. Good times. But dont be alarmed as we made it just fine. Since the boat comes at noon and low tide you must walk out to the transfer boat to make it to the high speed ferry.