Back in August, the wife and I headed to a place that was almost completely off the beaten path. Look up Cat Island, Bahamas.
The island is very skinny and about 60 miles head to toe. There are two "airports" (read: dirt paths) on the island accessible by turbo-prop from Nassau that run once or twice per day. The island is nearly entirely devoid of tourists and inhabited by locals who are some of the nicest people you'll ever meet. They love the tourists who show up because they get so few of them.
The beaches are absolutely pristine and untouched. You can look in either direction and see nothing.
As far as where to stay, we stayed at a very small "resort" (4 small bungalows) called Tailwinds on the north end of the island. The guy who runs it is an ex-pat from Brooklyn named Rich. He built the place himself (ran construction companies his whole life) and the place is very modern and clean, even has Satellite TV. He cooks for you whenever you want it, and he keeps a fully stocked bar that you just make your own drinks and keep your own tab.
When you leave, you square up with him.
Best vacation you'll ever take, and likely one of the most cost-effective. There is not much tourism there (yet), and the place is like $170/night. You pay for food/drink, too, but it doesn't add up to that much. We spent 8 days/7 nights there for $2500 including airfare.
Tail Winds Resort (Cat Island) - Hotel Reviews - TripAdvisor
Beaches that are 5 steps out your door (5 steps the other way to the bar!):
