Bonaire is our favorite. No schedule shore diving. Plenty of rental condos. Good grocery stores if you're staying for longer trips. We're planning a month trip maybe later this year.
We like Roatan but won't go back due to the sand fleas. Grand Turk was nice but groceries were hard to find, best to stay at one of the small all-inclusives.
My son (late twenties in age) took a G-tour hiking to Machu Picchu. He really enjoyed the experience. It was a younger crowd - perhaps an average age of late thirties or so. The small group was composed of people from Canada, and Europe; he was the only American.
It could have been that this was a hiking focused tour, but I have the impression that they cater to a younger demographic.