I'd just as soon not go through Corvallis myself, especially not with the coach. It's a bit different than when I went to OSU 42 years ago, and I wasn't enthused with the street arrangements even traveling in our pickup in 2013.
Despite possible temptation, don't make a sightseeing detour onto Oregon 242 at the west end of Sisters (at least not in the coach, but a fantastic tour in a toad)... just stay the course on 20. Take Oregon 34 west at Lebanon as Dave suggests, which takes you past I-5, through Tangent, and then nearing Corvallis hang left to stay on 34/20, skirting around the south edge of town and the University and pointed toward Philomath. This bypass is a relatively new wrinkle for us old Moo U's, and I found it a roomy, straight surprise the first time I headed east from Newport in the Beaver.
You could certainly go to Albany and then south on 20, as was my usual car route back in the day, and it may not be all that bad since it doesn't tack right through central Corvallis, but rather mostly follows along the river. But it's hardly the nice, smooth shortcut that 34 is, and you'd have to do a couple extra turns to keep on 20 and bypass town.
As Bill alludes, any of the roads through the Coast Range can do a lot of winding for some miles as you negotiate the hills. As noted, if a "curve ahead" sign recommends 35 mph, a car might do 45, but you should do 35... it's a good rule of thumb anywhere you drive a coach. Most climbs include passing lanes and the pavements are decent. Newport to Corvallis is a popular commute, so be prepared for anxious drivers stacking behind you here and there. On the winding sections, oh well, that's just too bad, but watch for idiots trying to pass when they shouldn't.
Joel
