This is a hard thing to get specific about because I have loved every place I've lived, and many of those moves were to an unknown city for a job. So I know wherever I land will be fine. But to stack the deck in my favor....
1. Scenic natural beauty, ideally with mountains on the horizon. Here in Africa I look out on high hills with the Olifants River marking the boundary between them and our land. My last home in the US was at the foot of Mt. Rainier with the hypnotic play of shadow and light changing throughout the day. A place where we slept out under the stars to watch meteor showers and hunting bats (would love to do that here in Africa, but leopards).
2. Animal life. As a retired veterinarian and college biology teacher I find animals endlessly fascinating. I will be living with cats and dogs so I need a community that will tolerate that eccentric connection. Here I study the curious giraffe at my waterhole who are also studying me, the nyala who grazes on the lawn, the shongololo millipedes who sense impending rain and I am thrilled to my core by the elephant who ignores the electric fence and eats all the landscaping, standing arm's length from the window. So ideally in Mexico I would have a small yard that I could make a quiet oasis for birds, butterflies and whatever indigenous wildlife was about.
3. Climate would be "typical snowbird" - 60-90º year round with minimal gray days. But I don't melt. I can live with very hot weather if a pool is available. A child's wading pool would be fine. And as to rain, hello! I lived in WA 17 years! As a native Californian, though, I thrive on that kind of Mediterranean climate.
4. As an introvert I can manage pretty well with Netflix and Amazon books and MOOC online classes. But in the best of all possible worlds there would be a movie theater and bookstore within driving distance ( say, 2 hrs), a community of expats to do things with every so often, a community need I can help fill (here, I am making eco bricks for schools to turn into benches and I am trying to organize a silent auction of all our possessions to benefit the Black Mambas, our all female anti-poaching unit). And my heart's desire, the one I am afraid is too much to ask for, is that I would find a couple of people who were willing to be amazed by the world to do day trips and longer ones. Travel and adventure are a blessing, even solo. But to have someone to share the delight with is priceless. Friends would be the icing on the cake, but I don't want to be greedy. Natural beauty, animal companions, books, pleasant weather and a way to contribute to my new community would be blessings enough.
Somehow this doesn't seem to have narrowed the choices down much...