Bend is cool to see and experience. It used to be my home base for a while, but the bougie-fication the last time I went rubbed me the wrong way, and I don't think I'll be going back anytime soon. Go eat at the Family Kitchen. It's one of the best soup kitchens I've ever been to. Shower truck and med clinic outside 2x/week. Not sketchy at all. Go and see Tumalo falls. Nothing can beat that Bend/Cascades skyline....
I lived in Eugene on Skinner Butte for like 2 months back in 2008. I went back recently and its....also not my bag anymore. But if you're looking for punk/skate/DIY culture etc. It's a great place to hang out. I'd usually busk around the bar-muda triangle.
I'm in Portland right now. I still love this city, but you have to get out of downtown to really see it. I like hanging out in Burnside, St. Johns, and Brooklyn. Mainly cause that's where trains are. Portland is also not the city it used to be. The homebums are gnarly, and I've seen some pretty bad violence up here the last couple of times I've been near downtown. I definitely sleep with one eye open in alot of places now.
I don't know if the Yamhill Pub is still kicking, but it was my first introduction to punk and traveling culture In 2007. It was a great bar last time i was there. There is also the Oregon Rail Heritage Museum in Brooklyn, if you're into trains.
Other places to see in OR include: Astoria, the entire coast (minus Coos Bay), Ashland, Hood River, McKenzie Bridge and the hots springs around it, Umpqua hot springs...
Avoid most of the southern I-5 corridor cities/towns. They kinda suck, and the tweakers are insane.