I don't have a source — it's just an observation based on my personal experience. The fine art world, musicians, and the entertainment industry lean left. You can find conservative painters, bands, and movies, but the default disposition for creatives is leftism. It's a personality thing. Creatives think outside the box, and push boundaries. Given the choice between something traditional and something radically new, creatives are apt to choose something radically new. So there's a correlation between the kind of aesthetic backdrop that might inspire a painting and the kind of people who tend to enjoy breaking tradition.

I've never heard that leftists rate as happier, and tbh that surprises me. My experience is that religious folks tend to be happier, and there are more religious folks on the Right.

With regards to urban versus rural, you have a good point. But cities along the West Coast and the inland places I mentioned became urban due to a confluence of people moving to a beautiful place.

If you have a rural town with a shockingly beautiful backdrop, before long there'll be oil painters, then art galleries, then hipster coffee shops, then yoga studios, and then the local socialist party headquarters. That's a bit hyperbolic, but there's some truth to it.