They do offer a wide variety of shore excursions in St. Maarten, one of my favorite Caribbean ports. You may want to consider doing the America's Cup regatta. They run the race right there by the port and it will not take up all your time, still plenty of time left to explore the town. I find the locals to be friendly and not overly pushy, so enjoy. I've also gone to Orient Beach, which is a cab ride from the pier, but plenty of cabs waiting there for the return trip....Have fun whatever you decide to do.