Hwy 22 has a nice shoulder.
I have a couple of suggested changes to the Reach the Beach route and included them on this link to Google Maps.
When you get to the end of the Willamina/Sheridan Hwy, pass under 22 and link up with Yamhill River Rd. This will keep you off the double lane section of 22 which is real noisy. You can link back up at the overpass of 22 or ride all the way to the Fort Hill Lounge and Restaurant and walk you bike over a little gravel to get back to 22.
Instead of turning on Hebo Rd right after the narrow bridge on 22, ride to Grand Ronde and turn on Grande Ronde Rd. The initial stretch of Hebo Rd is narrow with blind corners. It's also uphill. If you wait until Grand Ronde to hook up with Hebo Rd, you'll miss a little scenery, but it's safer with no climbing. (You could also hit the buffet at Spirit Mt)
Hebo Rd can either be busy or empty. It depends on the day and the time. Lots of people use it to get to Tillamook. The Little Nestucca River Rd which you'll turn onto from Hebo Rd is very pleasant.