There are lots of pretty islands in the Caribbean, so folks have been understandably puzzled by our going somewhere that requires as much planning as does traveling to Cuba, but ever since seeing his home in Key West last year and his grave in Idaho the year before, I’ve badly wanted to see where Hemingway spent most of his final 20 years. And so, on a Saturday morning at 8, we climbed into the back of an ’89 Peugeot and headed east 10 miles from Havana. Our first…