There is a ton of ground east of the Hwy between Carnation and Monroe. Much of it is private timber company land (Hancock), you may need a permit, but there are a few sections of state forest in there. Do your due dilligence and find the property lines.
Once you find the boundaries and know where you can/cannot access, use Google Earth to find potential areas. Park at a gate, start walking. If you get back more than a mile, you will effectively eliminate 90% of the hunter competition. Find a young clearcut that has growth in it but still allows you to see. If you sit and glass these cuts all day, you will most likely see animals. Its boring, but effective.
You can also creep the timberlines, or find some old timber with ferns and creep through them. If you think you're moving slow enough, move slower. Mature blacktail are the hardest deer to hunt, especially in timber. THey are true ghosts. There one minute, gone the next. Often all you ever see of them is a flash of white and a flick of the tail as they are leaving.
The last week of the modern firearm season will be your best bet at a mature buck, as they are just going into the rut at that point. I would find an area that has old rut sign, learn it in the early part of the season, and then spend as much time there as possible during the last week of the season. Every day during that last week, the deer will get more and more active. Make it a priority to get out on the really nasty rainy/windy days. Those days bring the deer out into the open.
Hope that helps!