Highway 22 is okay. I travel it often, as I live near Hebo and it is fine. I take my 40' mh pulling my race car in a 24' enclosed trailer to Woodburn via Highway 22 and as long as you take it easy you will be just fine. Bicyclist really only use that route during the Reach the Beach charity event which has already taken place this year.
I would recommend turning right at the Catholic church in Grand Rhonde to go over to highway 18. It is much easier than going all the way to Valley Junction to get on highway 18.
Paul