For Bend, if you like mountains and twisties, take 20 North to Sisters, then make a loop of 242 West to 126 North, back to 20. Then you can take 20 back to Bend. It's about a 130 mile ride, but spectacular!
If you can take the time, and don't mind crisscrossing the Cascades, you should really try to catch 224 between Estacada and Detroit. It's sport bike heaven. There are lots of paved NFS roads to make it a shorter run, but since I was turned back on NFS25 last Saturday by a road still closed due to snow (in July?!?), you should stick to the marked highways.
If you post more info about your trip, like how much time you have to spend exploring, more routes could be suggested.
I'm going to have three days in Pullman and one day around Bend. I am going to do the loop through Sisters. If time permits I will check out 224.
Thanks for the input. I can't wait leaving in two days!!!