If your coming thru on I80/I84 then US101 is a must see. Unless you love freeways there are lots of alternatives that are much better. For instance take I80 into NV and drop off onto hwy 140 through southern Oregon. Great scenery, and that will put you just a ways south of Crater lake. Then down the hill to the Oregon Caves. From there Crescent City CA is not too far.
If Portland is a destination for you, then about 40 miles North on I5 and take the Longview,WA exit and follow the signs to Astoria. From there you can spend a week moving down the coast a little at a time to Crescent city area.
Let us know exactly why you put Portland in and we can make lots of suggestions for alternate roads.