Thanks for the question. I suggest a trip east on Highway 126 from Eugene. You can raft on the McKenzie River. There are numerous guided trips. I highly recommend Helfrich Outfitters and if you want to begin and end at Belknap Hot Springs Resort check out High Country Expeditions. To get a great view of the Cascades take the scenic drive up Highway 242 a few miles from Belknap Hot Springs to the Dee Wright Observatory at the highest point of the road. You can climb to the top of the observatory and view 360 degrees of the Cascades with a cool compass of sorts, that helps you figure out which peak is what.
You can fish in numerous spots along the McKenzie. Some popular places are at Leaburg Dam and along the shore. One of my favorite places to fish is at Clear Lake at the headwaters to the McKenzie River. You can rent a row boat and drop a line in and troll while you take in beautiful scenery atop strikingly clear water. (Here’s a tip if you do- use corn as your bait, with a very light weight sinker). In Eugene, you can also find some decent fishing near Autzen Stadium in the Alton Baker Canal and in Junction City at the Junction City Pond.
I hope this helps. Let me know if you have any more questions.