Lero, a really pleasant ride (scenic, low traffic, & no hideous climbs) is from the end of the MAX in Hillsboro to Yamhill, detailed here:
http://www.portlandonline.com/shared...e.cfm?id=93918
From Yamhill, i think the best bet is Hwy 47 south to Carleton & McMinnville - it's got traffic but I believe there's a 3' or so shoulder for most of the way (the State bike map confirms this).