I'm trying to plan a trip for my folks next year and don't even know where to begin. The only time I've gone, I stayed with friends.

Background about my folks:

They're 66 and 70 and reasonably active for their age. My mom's knees make hiking hard, but they'd like to see what my dad calls "ecological wonders". They like resorts, but are the type of people who are happy with smaller places as long as there's a pool (my mom really likes to be in water). Their Spanish is decent, they like getting to know people and leaving resort areas, and they like drinks.

Any ideas?