1st thing you need to do is extend the trip for another week if at all possible. The single worst thing about the SJs is leaving them.
One of the biggest kings salmon I have seen from the Sound was caught off the west side of San Juan from a sail boat. My buddy and his wife were waiting for a pod of Orca to show up and he was just killing time. It was just under 40 lbs and hit a funky chicken spoon behind a flasher. He DID NOT have down riggers on the boat. You can cheat by hanging a large cannon ball sinker off of a downrigger release and attatch the release to your line about 30 to 50' in front of your flasher. (AKA poor mans downrigger) When you hook a fish just reel in until you or your wife can pull the release off of your line and then continue to fight the fish into the boat without the weight on your line. Depending on the release and the rod and line you are using you can go up to a couple of lbs of weight and get fairly deep. If you get out early and find bait on the surface you don't need to be deep at all for Kings (10 to 35' the first hour of light) . Be sure they are leagle if your going to keep one. Another very affective option is what we call mooching and motor mooching bait. Youtube it. That will work from the surface down to a couple of hundred feet depending on drift speed and weights used.