+1 on the multnomah falls visit. Impossible to walk to. Its a bit out of town (east) a quick car ride but no chance of walking.
pdxtony at that yahoo place if you want to check out a few things with a car.
Also check out the local PDX Tanner goods.
Seattle has a commuter train from PDX if you want to spend a day up there. (if you can stop in Tacoma check out The Chihuly glass museum or take a tour of their foundry area)
goodwill downtown has a boutique shop but with...