Lots of good mountain biking around the Hood River Valley, Post Canyon being the premiere location, and my personal favorite.
There isnt a whole lot of anything between Bend and Hood, but if your in to climbing definitely go to Smith Rock outside of Redmond. Its right on the way and world class.
Coast doesn't get great weather this time of year, so i wouldn't recommend that, But Portland is always an awesome city to check out, definitely hit Vodoo Doughnuts in the Pearl district, and Check out OMSI if your into hyper-interactive museums. Microbrews are also great if your 21.
Hope that helped. ask away if you want to know more