In seriousness, the family part is really hard. I would say it partially depends on how mobile your relatives are. My in-laws are homebodies who don't like to travel, period. When we lived far from them, we saw them once a week for a year, and they were retired! My parents both work, yet they visit us ~3 times a year, and we visit them, twice usually. And if/when my mom retires she would definitely either come stay with us for a couple months or relocate near wherever we live. This might be a good reason to look near major airports- if people can hop on a cheap, direct flight it is easy to visit compared to puddle jumpers between small city airports.
I highly value living near like-minded people. That is the top of my list (and why I could never do FL, bible belt, TX, etc). If SAD bothers you, you might consider that sunny places, while cold, will be significantly better for you- I think CO, NM, AZ, etc are very sunny even in the cold areas. We like the culture of college towns- they have things that bigger cities offer with typically a lower price tag and smaller community feel, and are usually super walkable/bikable. They tend to have great K-12 schools with lots of opportunities, and they are used to people coming and going so making friends is easier IME.