'nucks, 99W has a bike lane/decent shoulder for almost the entire stretch to Newberg, but it's really ugly: high traffic with a lot of auto-oriented commercial crap. Guaranteed bad 1st impression of Oregon.
I have some other possibilities in mind, but first let me ask: where's your second night destination? On the coast, or at one of the BLM campgrounds along the Nestucca? Let me know before I float suggestions that are moot...
also, if you haven't already found it:
has good info (well i better say it's good, since i created it
on touring around Portland and NW Oregon. There's some pdf maps of the Nestucca route, too.