I was in Grand Turk in September. We caught a cab to the tiny little town and then we walked way up the beach stopping to swim along the way. The lighthouse is pretty way up at the point but there really isn't much there. My honest opinion is that if you want to swim and do just a little snorkelling you can do that at Governor's beach which is very close to the pier and I believe there is a little trolley that runs back and forth. The snorkelling isn't outstanding but it's not bad. We had dinner with a couple who had taken an excursion for snorkelling and they said they had an amazing time. Grand Turk is still very undeveloped but in its own way it is really charming too. It's a nice slow, easy day.