A cautionary note - there are lots of panhandlers and homeless people in the city. This was the only discomfiting aspect of my Portland visit (in July, also for a conference). Also, if you want to just blend in with the locals, dress way ... waaaaay casual. To cut down on luggage, I took only three outfits w/ me, and wore them in rotation everywhere. Even "science conference casual" made me feel conspicuously well dressed in public, and was probably a factor in attracting unwanted attention on the streets.
This is largely true of some parts of Portland. Downtown business attire is similar to Seattle. People want to believe that Portland is more laid back and funkier than it is. And, yes, just like Seattle, there are aggressive panhandlers. But compared with SEA or SFO, Portland's panhandlers are a lot more calm. I've never been followed into the street by an aggressive panhandler in PDX. SFO, on the other hand.....
