It can be easy to overcomplicate the idea of retiring overseas, but, the truth is, in many ways, it's not much different than making a move within the States. In some respects, you could say it's easier. What makes it difficult is that you're working from a blank slate.
Quirkiest retirement haven in the world? That'd have to be Belize. Belize City's roadways are built around a system of roundabouts (thanks to her British colonizers), but shops alongside them sell rice, beans, and tortillas still ground by hand. Everyone you meet speaks English (it's the country's official language), but this belies the stories of their origins.