I tried this before, but for some reason, the post didn't make it.
First, I will say that I'm far from a Rock Lake expert, or any kind of an expert for that matter, but I have fished this lake a few times and have heard a lot about it from my fishing friends in the Spokane area.
The lake has browns in fairly good numbers and big fish. I know one bass guy who claims that the lake holds the state record brown. He mostly fishes the steep banks with crankbaits and thinks the fall is excellent. Rock also has largemouth bass, panfish, and rumors of smallmouth and walleyes being planted by the bucket brigade.
This is a tough lake to fish without a boat, although I suppose you could use a pontoon or float tube in the bay near the launch and other places where you can get access to the water.
This also is a tough place to fish with a boat until you learn the lake. The launch is pretty rugged, unless it's been changed in the last five years. There are a LOT of rocks and offshore structure that can clean the lower unit off your outboard in a heartbeat if you're not careful. You can be running in 200 feet of water and see rock shoals just inches below the surface right beside your boat. Scared the socks off me once with that one.
The biggest boating problem is the wind, though. In the scabrock country, the wind blows twice a week, once for four days and once for three-- or so the old joke goes. However, since much of the shoreline of Rock is steep cliffs with little or no shelter, when the wind comes up, you can be in trouble unless you've got a boat capable of handling rough water. You have to be very cautious when fishing this lake...more so than just about any other.
All that said, the fishing can be very good. I never did fish it specifically for trout, but while I was bass fishing, I would see shoals of foot-long fish cruising just under the surface.
Good luck.
Can't say much more than this as I haven't fished it in five years.
