I can tell you about the coast from Aberdeen south to Raymond on hwy 105 The trip between Aberdeen and Westport is breathtaking lots of ocean scenery and the cranberry bogs are cool Traffic is not bad and for the most part you have good shoulder to ride on. when you get close to Westport There is a very wide shoulder for the duration of the trip. you will travel inland a bit until you get south of Grayland then its it just like the Oregon coast. Take a camera, I would plan this trip for late spring or summer. The weather can be prett dicey over ther efrom October until May. Lots of wind and rain. What route are you thinking of when you reach Washington I may have some insight for you on that also.