My advice would be to avoid US97 south through Oregon as much as possible. While a few bits are OK, most are horrdily straight slogs through unattractive territory. Particularly awful is the section between Bend and Crater Lake, straight, slow and hot. Oregon 20 is similarly dull and hot.
Unless you have a reason for going all the way across Washington to 97, you might think of dropping south a bit further east. Hwy 12 from Missoula MT down Lolo Pass to Idaho and points west is superb. South from Lewiston Idaho through Asotin and Rattlesnake Grade (OR3) across the Grande Ronde River and into the Wallowa Mtns. (Joseph) is exceptional riding (best pie and ice cream on eath at Boggins Oasis at the bottom of RS Grade). West from LaGrande OR on 244 to Ukiah is a serene sweeper heaven with no cars. US395 from Ukiah south is beautiful through the Blue Mountains. US26 has some lovely parts as well.
The national forest roads (stick to the two-digit variety) are awesome across most of the state. All the roads through the John Day River area are sublime, as are the ones mentioned above. Mackenzie Pass was closed four weeks ago, but if its open, its a must-see. The forest road around Cougar Reservoir between OR126 and Westfir/Oakridge is superb. Take a couple extra days and just criscross the Cascades and coast range.
The lodge at Crater Lake is excellent, breakfasts or afternoon brews on the patio overlooking the lake heavenly (if you can get a reservation; although even if you don't stop there for breakfast or beers!). If not, I've stayed at Cater lake Resort, a few miles south in Fort Klamath (http://www.craterlakeresort.com/
) in the nice clean cabins.
Phew, I could go all day!
Have fun. If you need any help route planning, send me a PM!