I met up with some divers from a cruise last year. There were 8 in the group and they went to Cas Abou for a morning dive, I joined them and 2 of them followed me to Westpunt where we enjoyed exploring Alice In Wonderland for over an hour. They had time to go back, pick up their beach loving companions and even had time to see the floating bridge etc. before having to be back on board. If you rent a car/or get a group together the nondivers might enjoy seeing one of the National Parks or going on a beach tour while you go on 2 shore dives. In the East divers can go along the wall at Director's Bay and join the others at the Tug boat, see the wonderfully wacky folks at the Dive Bus or contact them ahead and either drive with them or meet them at the dive site Du jour. I'm more familiar with the west end sites and can suggest Habitat, Porto Marie, Cas Abou, Lagun and of course here in Westpunt for divers and mixed groups. I wouldn't suggest squeezing in renting a car, traveling to different sites, 2 dives, lunch, relaxing, returning rental and seeing some of the town if this other group hadn't done it so easily. Maybe they will see this and post. If you decide to go with an intown op that can pick you up at the boat in time for the 2 tank boat, you'll still have hours to walk around the town near the ship. The Slave Museum is at the Kura Hulanda Hotel, quite near where the Holland America docks. The floating bridge and market are within sight of the ship and the Maritime museum and synagogue are just a short walk away. Enjoy your cruise.