If you have time, a drive out to Helvetia Tavern for food and drink is unforgettable. It’s very pretty in Hillsboro as well.
No car? I’d take MAX train to Pioneer Sq and explore. Lots of sThen maybe hop on MAX and just go in different directions to see the city.
With Car: Check out the bridges and get different views of the city, its so pretty. My favorite bridge is the St. Johns Bridge with Cathedral Park under the bridge.