As another very liberal person, but one who started in the SF and ended up in a very small, rural, conservative Alaskan town, here are a few thoughts.
I've always like mid-sized college town, especially those with pretty elite schools. Northampton, Amherst, Ann Arbor, Madison, even Lawrence. Eugene in Oregon. There's a lot going on culturally and intellectually without the traffic, dirt, and crime problems of big cities. Also, property values aren't so crazy so you needn't work so many hours each week to pay the mortgage.
Although Seattle and Portland have big recreation (overnight stuff and skiing) closer than the Bay Area does, the regional parks in the SF area are real gems. To take a 3 or 5 or 10 or 20 mile hike before or after work from a trailhead 20-30 minutes away (0 to 3 minutes if you find the right location) is not available to most people. And as much as I self-identify as a backpacker, I have to admit that more of my miles each year are on day hikes and day ski trips.
I'd also point out some of the advantages of smaller more rural towns: Housing and really spectacular land is far, far cheaper. We know MD - MD/PhD couples who struggle with their mortgage for a very boring SF house. They aren't on the 13 acres of spruce forest with 700 feet of sandy beach and views across the salt water of glaciated volcanos that we have. And our house payment looks more like the electric bill than a CA or WA house payment. On top of that, professions pay better here. Sometimes a lot better. That seems backwards, but it is supply and demand. Docs, lawyers, engineers, etc, gravitate to the big cities and there is an oversupply. Any professional with a pulse can hang their shingle in a small town and one with some skill and dedication is quickly fully booked and greatly appreciated. We each work about 3 days a week and therefore have time to be with our kids, volunteer, exercise, and travel. That wouldn't be so easy in a metropolitan area. Sure, I'm the only un-armed, truckless guy I know, but I still get invited on hunting trips because I'm a heck of a sherpa. And while there aren't many liberals, we got to know them all very quickly so we actually felt much connected after 6 months in town, than after 3 years in Seattle.