I live in western Washington state. The open drive-ins are :
Skyline (in Shelton, where I worked for ten years till new owners took over 2 years ago and ran it into the ground. This is a single screen. New owners have let projection, sound, kitchen and restrooms go to hell. They jacked up prices too. This used to be a nice theater but not anymore. Not recommended--stay away)
Rodeo 3 Drive-in (in Port Orchard, has 3 screens, sensational FM stereo sound, the brightest picture on the west coast, and brand new playground equipment. Great food and a huge menu. Just finished some major upgrades and remodeling including fully computerized boxoffice and snackbar with credit/debit cards accepted. Very highly recommended!)
Wheel-in (in Port Townsend, has nice indoor seating. Quaint little 150 car theater done up as a western ranch theme. Recommended.)
Valley 6 drive-in (In Auburn, has 6 screens but is being run into the ground. The place is a total dump and very dirty, has bad projection, AM radio sound only, screens are covered with moss and pictures are very DIM, food is awful. Same people that are now running the Skyline in Shelton. Not recommended--stay away)
Puget Park (in Everett, Single screen, has recently cleaned up the place, new paint, new projection equipment, great sound, good food. Recommended))
Blue Fox (in Oak Harbor near Whidbey Island Naval base, single screen, open year round, good projection and sound, good food, has a seperate game room building with all kinds of games, they have a go-kart track operating in the summer. Very nice theater. Recommended.)