A problem is that once you make good friends if they're transplants, they move away in a few years when they get priced out or go back to live near family.

It completely depends on the neighborhood. I've lived in some where the neighbors brought over fresh baked cookies (yes in Seattle) and I invited them in and we chatted and became friends. Other neighborhoods, people pretend not to see you and turn away if you wave. There's no universal Seattle type, and you never know until you try to connect.

Port Townsend would be the most progressive but it's not close to Seattle. As you go beyond the Seattle burbs, the small towns tend to be conservative.