Another option is to simply stay on the Trans Am to the coast. I did much of the OR section of the route during Cycle Oregon 2002. While I fond some of eastern and central OR somewhat borning (and hot and dry even in early September), McKenzie Pass east of Sisters is a terrific ride. It's an old volcano that blew a long time ago. At the pass, there is nothing but black lava rock. There is an observatory built out of the stuff. It looks like a place Skeletor would call home. The climb up the east side is not that bad. The west side has a cool section of tight switchbacks through forest. Descend with caution.