Joyce,the best choice for you in north west Oregon is Cannon Beach rv park, less than 30 minutes south of Astoria. (cbrvresort.com). From Portland, we use the highway along the Columbia, through Astoria to Cannon Beach.
For us, coming south from British Columbia, after border clearance, it's all freeway to the Washington Oregon border. We fuel once prior to entering Oregon over the Lewis and Clarke bridge in Longview.
Last trip I found myself south of Portland, looking for a "better way". Signage made me miss my turnoff but after turning around we made our way to the coast. This particular roadway was narrow, bumpy and full of hills as we approached the ocean.
The destination is always the Pacific so I am without answers for inland.
Which route would take you westward??