Check out this mid-valley ride on Aug 15 in the foothills of the coast range. The ride returns this year after a gap in 2008. They have now added a century option to what was the Alpine Half Century in 2006 and 2007. I rode it in 2007 and it is a very scenic route. There were only 60 registrants that year. It also has more challenging hills than the typical organized event ride in the valley (like Monster Cookie, Peach of a Century, Covered Bridge Tour etc.).
I rode the 50 mile route twice last summer, but out of Philomath, so made it 60 miles.
If you do either the 50 or 100 mile route (or neither), come on over to Newport the next day and ride the Yaquina Wheels Lighthouse Rides: