I haven' t spent much time in the woods of Cowlitz county, but the little time I did spend there didn' t show me much for turkey sign. Slee is right about the Lewis county birds, just small groups but they are gaining ground evey year from what I can tell. I wouldn' t venture south of Castle Rock on I-5.
Two of my daughters live across the Columbia from Longview/Kelso on the Oregon side and my time scouting Columbia, Scapoose, and points west haven' t been very fruitful either. If I was intent on staying on the Washington side of the Columbia, I' d suggest the White Salmon drainage or any number of likely areas in Klickitat. Just my humble opinion.