I find that the best places to hunt grouse in western Washington is in the cover along creeks and lakes, along old logging roads where the grouse frequent for gravel, and in the berry patches in the alpine areas. Newer growth forests are good because of the larger amounts of food and cover. I find that grouse hunting is about finding that happy medium of hunting cover that is heavy enough to hold grouse and still not too heavy to get a shot at a flushing bird. I have been frustrated by flushing birds repeatedly that you just can't see. If you're running a dog, alpine berry patches are probably your best bet. In the heavy stuff my dog finds birds well within range, I can't see the dog or the flushing birds. I'm hoping to go this Friday when the temps are suppose to be in the 60's vs the 80's we are having this weekend.
Best of luck, let us know how you do.
Dave