We were in this same place three years ago -- looking to move out of the upper midwest to a nice small town or rural area. Our approach was to think hard about our 'must haves' and our 'nice-to-haves.' In the end we came up with a short list of things that any new place HAD to have, and then a couple of things that would be the cherry on top of the sundae.
FWIW, our absolute must-have list was: milder weather, lower taxes, excellent access to outdoor recreation opportunities, good climate for gardening, not too conservative politically.
After you get your list together, stick your head deep down the internet information rabbit hole and start gathering a list of potential areas/towns. As you said -- that type of information is readily available on line. One line of searching that was fairly fruitful for us was googling "best small towns" and "best small towns for outdoorsy people", "best small towns for retired people" -- things like that. There are millions of internet 'list' articles out there. Just skim through them all, and you will start to get ideas. Keep an open mind, and keep referring back to your list of must-haves. If you find a town/area that ticks all your boxes, put it on the list of potentials. And start researching that place in more depth.
Next came the intangibles, which is what I think you're really asking about? After we gathered a list of potential areas we might like to live, we went and visited them. We just started at the top of our list with the top contenders and worked our way down. It was fun and very enlightening -- vacationing with a purpose. When you visit a new potential area, drive around and walk around. Visit the Chamber of Commerce, and also talk to people. All sorts of people -- the clerk at the hotel, the cashier at the grocery store, someone you run into at the park. Ask them the questions you really are curious about, like "how friendly is this town to newcomers?" "What's the best grocery store?" "What are the things you
don't like about living here?" "What's the
best thing about living here?" In general people like to talk about where they live, and they like to give advice.
Visiting tells you a lot, but it's different than really
living somewhere. If you are getting really serious about an area, you can also post a question here on the forum to get the MMMers' takes on the intangible pros and cons. For example,
@FINate posted a question recently titled "Convince me that Bend, OR sucks." He is considering moving there, and specifically was asking for the negatives about Bend from people who know the area well.
https://forum.mrmoneymustache.com/ask-a-mustachian/convince-me-that-bend-or-sucks/ If you can come up with a grabby title for your post, and clearly state what your must-have list items are, you'll get some good ideas from the forum members. We have smart folks around here.