You might try either Howard Lake or Martha Lake west of the Smokey Pt. I-5 exit and towards the end of Lakewood Road. These are the last two out of 8 to 10 lakes in this area. People tend to hit the ones closer to the freeway first. Even when Martha is the only year around lake open in the area (except for Gissburg Ponds), I've only seen light pressure on this lake. Howard is a small lake just to the southeast of Martha that I've heard is quite nice to fish. Haven't been there yet.

Still, Martha is about an hour from Seattle and holds big fish. I scored an 18" rainbow and a 16" hot on its heels not long ago. The lake also holds cutts and, I've been told, browns. At the time of that outing, I was one of two boats on the water, and that's typical for all the times I've been there--low pressure.