What's wrong with catching a few whitefish?
The Cowlitz and Kalama are your only SW WA options this time of year for trout, pretty much everything else is closed. Cowlitz is open all year for cutthroat because of the hatchery program, and Kalama is open all year for trout because... well, I'm not sure why, but it is. McKenzie and Middle Fork are the rivers on this side I would consider "good" fishing.
Also, I don't know about Washington, but in Oregon, you are effectively allowed to fish for whitefish year round because according to regs they are "open during trout, salmon, or steelhead seasons". If it's open to any of those three, it's game on for whitefish. They are always fun to nymph up when you can't catch much else.
The Cowlitz and Kalama are your only SW WA options this time of year for trout, pretty much everything else is closed. Cowlitz is open all year for cutthroat because of the hatchery program, and Kalama is open all year for trout because... well, I'm not sure why, but it is. McKenzie and Middle Fork are the rivers on this side I would consider "good" fishing.
Also, I don't know about Washington, but in Oregon, you are effectively allowed to fish for whitefish year round because according to regs they are "open during trout, salmon, or steelhead seasons". If it's open to any of those three, it's game on for whitefish. They are always fun to nymph up when you can't catch much else.