The active waterfowlers that I know appear to spend a bit of time at http://www.refugeforums.com/refuge/forumdisplay.php?f=36. On the west side it sounds like most folks head up to Padilla Bay and others with boats big enough for the conditions try the Skagit delta. I've had more luck hunting the Potholes Reservoir and surrounding areas near Moses Lake. Although east of the mountains can be crowded at times, spots on the west side can be impossibly so.
It sounds like birds are finally starting to come down from the north with geese leading the way. Like anything in the outdoors things can be phenominally good or sanity testing bad. Best of luck.
Both sides of the Cascades offer excellent waterfowl hunting. There is a lot of public lands that are available for hunting. One good source is Washington State Depart. of Natural Resources. They can provide you with maps showing land ownership for almost all of the state and the cost is minimal. You might consider giving them a call in Olympia.
Before the water ices over the area around Potholes Reservoir can be good. As things freeze up the action generally shifts south to the Tri Cities. However some years if the feed is good the ducks will raft up on the Columbia and work the area corn feels around Moses Lake.
There is lots of hunting area all along the Columbia and it is not all crowded. A mile walk from a crowded parking lot will most times give you solitude and a lot of birds to yourself.
Cherry Valley near Duvall attracts a few waterfowlers. There's a permament blind built on the east end of the parcel on a permanent pond. Ducks are going in there every evening, and while the action won't likely keep your guns a-blaring all day you'll likely see some action the first hour of the day. I live about 1/2 mile by way of the duck from there and hear the shots every morning. Myself I like to hit the Central Basin for ducks so I don't hunt them over here.