Go to G.I joes in Issaquah, they know what they are doing. In terms of what kind of fishing you will want to do, I would stick to the basic perch/panfish deal and all you need to do really is go to any dock at any time of the day, well maybe not at the heat of the day when all the swimmers out, but around 9-12am and after 5pm ish and drop down a worm with a weight and keep it about 2 feet off the bottom or just over the weeds and you should do plenty well with perch which can provide plenty of fun for your son...You can pick up a dozen nightcrawlers at Fred Meyer for $2 bucks and that should last you a few outings....Depth wise I would say oh anywhere from 10-40 feet but usually straight down from a normal dock on the lake usually will hold plenty of perch and panfish and maybe an occasional bass or trout or something to really make the trip special. Anyways hope you get your son hooked to fishing and you get to spend some time with him catching fish. Hope this helps, I can give much more info if needed, but I fish on the other side of the lake as opposed to the seattle side where you are. But good luck!