Are you looking for a spring or fall hunt? WA has a HUGE population of merriams on the eastern side. Most people who hunt turkey here talk about Kettle Falls as the place (actually, all up and down that area is packed with birds)... Not only that, if you bag your bird early, you can head over to central WA (Just outside Dayton along the Tucannon) and bag a rio... if that goes well, head to the western side and try to finish up with an eastern (tough to find and hunt, but definately out there). For more information
WA Turkey Hunting