This is a fantastic answer. I have no experience of ever living in California, but I've heard from a number of people that large swathes of the state are way more conservative than people think. Funny how much of the country views the "left coast" as "flakes, fruits, nuts" and ultra liberal. Nope. Only parts of California are that way, and it's been my observation left/right-ish (it's often not that simple) political leanings have a lot to do with whether a place is more urban or rural. So in cities, there is often more tolerance because people have to get along and coexist. In the country, people can be defensive of their property and resources, suspicious of anything that is different, etc. It just sort of naturally nudges populations in certain directions, if not in an absolute way.
Also, cities being population centers, it is easier to date. When you're in the country, and you or your date has to drive an hour to meet up, that's tough. Unless long distance relationships are your thing...
Then there are your regional attitudes. The east coast, I found was less surface-level friendly but more genuine. The west coast was extremely friendly and welcoming, but just under that veneer, was a tendency to use people and backstab them. Lots of fakery. In the rust belt cities like Cincinnati when I lived there, it was all survival, but the punk and arts scene was pretty interesting. Establishment versus subversive youth was the vibe I got there. The midwest (Iowa) was all down to earth common sense...people were very friendly, and wouldn't necessarily screw you over, but didn't want to talk about uncomfortable topics very often. I don't have much experience of the south...but I know I like the food.
So with that in mind... I'd expect in west coast CITIES (some of them, especially the big ones, and especially in OR/WA) to easily meet people and make friends, but to discover unpleasant things about them or be surprised by how they acted once the true colors started to show. On the east coast, I'd expect the opposite...finding your people and getting your foot in the door may be a challenge (you really almost need to know somebody) but once you're in, people will connect with you in genuine if sometimes harshly honest ways. I wouldn't even try to be involved in an alt lifestyle in the midwest, though I'm sure plenty of people do.
Now Colorado... Colorado is lifestyle heaven. But here in the Springs, we keep it pretty shush. We're a little afraid of outsiders coming in and shaping things or overpopulating too much (we already have water shortage problems.) So we let you all think it's a mecca of ultra conservative right wingers and religious pundits, we let Focus on the Family scream and holler and scare people off. And then we quietly gather by the hundreds at the gay bar and the kink club and the private parties, or drive up to Denver for one of the biggest kink conventions in the country, etc. I know a crap-ton of poly people here. But until I got on fetlife and found our alt community, I had NO IDEA. And so many people, even natives who have lived here their whole lives, are shocked to find out what people get up to...
As for our regional attitude, I've found it to be a perfect mixture of everything I've named. Down to earth but sophisticated, artsy and funky...friendly, yet genuine. A cool blend of realism and idealism. I've never lived in such a "just right" place, ever, and I've lived in lots of places.
I'd go for cities that have active and growing poly communities rather than thinking about states. States are BIG. Where in California are you? California is enormous and some areas are extremely conservative.
