Greg, here's some maps & resource info. on touring around Portland, especially to the coast:
http://www.portlandonline.com/transp...x.cfm?c=36638&
one of my fave coast trips is :
- Hillsboro MAX to Banks, out 6 to Timber Rd.
- Timber Rd. north to Vernonia
- toward Astoria via Mist/Birkenfeld/Jewel

*
- at Otis swing around Youngs Bay

*
- then south on the coast on the Lewis & Clark Rd. to Seaside
- south on 101 to Tillamook
- around Cape Meares/3 Capes loop

*
- south on 101 to Beaver / Nestucca River Rd.
- inland on Nestucca river Rd.

* to Carlton,
- back roads to Hillsboro MAX
* = very scenic and low traffic segments
Don't know how many days this is -- depends on camping/where you want to stay -- maybe 4 or 5 max. ??? Also the bus from Tilamook to Portland can shorten the loop.