Crater Lake National Park is between Bend and Medford. It's about 35 miles around the lake, by road. Equal amounts climbing and descending ... fantastic views.
The "Century Drive", west/southwest of Bend.
If you like to climb, ride up to the Newberry Crater / Paulina and East Lakes, south of Bend a ways.
"Old 99" from Ashland up toward the Siskiyou summit. Nice descent on the way back.

The Cycle Oregon ride was in this area sometime in the last few years, and there's a sponsored ride / loop down there in September - forget the name - you might be able to find that route.

Get the maps for the NWT rides, and look for other roads in the area.

Take a look at the Oregon Shakespeare Festival's schedule and try to take in one of the plays (ideally one of the outdoor, evening ones) before the NWT ride.

It does get warm in the Medford area in the summer. Earlier in the morning is cooler.