Yacht Clubs cover an entire range. For example in your area, there is the Seattle Yacht Club. We have friends who are members and they love it. All kinds of social activities, committees, cruises, many private out stations, etc. It is (on the scale of yacht clubs) fairly expensive, but it offers a lot. On the other end, is the Point Roberts Yacht Club. No club house per se, few assets, regular sailboat races, organized cruises, no out stations, but very inexpensive.
Just 2 clubs at somewhat opposite ends of the spectrum.
My advice would be to try to talk to several members of any club you consider to get a feel for that particular club and it's members before joining.