From two-story villas in St. Vincent to private-island retreats in Belize, these are our favorite ways to stay over the Caribbean. You can see the water through your bedroom floor. Outside, a ladder descends from your deck into the sea, and your private pool gives you another place to cool off before breakfast arrives. That’s the appeal of overwater bungalows, a relatively recent addition to much of the Caribbean. Over the last decade, they have spread beyond their traditional stronghold in Panama’s Bocas del Toro archipelago to islands including Jamaica, Antigua and St. Vincent. Some...