Our friends moved to Vilcabamba, Ecuador and also love it. Temps are in the 70's year round, food is cheap and good medical care is available for decent money. Lots of hippies, econuts and other assorted eccentrics live there so it's not for everyone. Cuenca has similar weather, is out of the earthquake and volcano zones and is extremely popular with non-hippie expats.
Wherever you choose to go, take the experienced expat's advice: don't do anything that can't be undone in 5 phone calls or less for at least 6 months to a year. In many of these places it's extremely easy to buy a house and extremely hard to sell it once you do. Rent until you know for a fact that the area you are in is where you want to settle in permanently. In fact if you are retiring as a senior it may make more sense to rent permanently than to buy so your heirs won't have to deal with disposing of an estate in a foreign land. Plus you won't have to worry about maintenance as you get older and it becomes more difficult to get about. Take time to travel about and see what climate suits you best. Costa Rica, for example, has 27 different temperate zones ranging from steamy jungles to tropical beaches to cooler mountain temps. Don't lock yourself in to the first place that catches your eye. And finally keep in mind that if you want to leave America you also leave the creature comforts Americans are used to. Sure, you can make a seamless move to Panama and have every comfort you had back home but it will come at a price that would have made it cheaper to stay put. If you don't mind simplifying and living like a native then you can have a wonderful retirement. Good luck in your search.
If Ecuador is so great, why are we letting so many “refugees” in here from there?