Both the Willipa Hills trail and the Olympic Discovery trail are getting better with age. If you don't want to mess with riding out to the coast along the Columbia River take the train to Centralia and start there. Follow the Willipa Trail until conditions warrant hopping on the road. (Parts of the "unimproved" section can be unrideable if they haven't mowed.) Aberdeen to Forks is not very interesting riding but then you can take the Olympic Discovery trail.