For a day trip, I really like going to the Columbia Gorge. You can take the highway on the Oregon side to Hood River or beyond, and then come back on the Washington side. Hood River is a really cute town. If you want to come the long way back, you could drive up to Timberline Lodge from Hood River and then back to Portland. Wonderful scenery.
Another great day trip is Astoria - Cannon Beach. Cannon Beach is a cute town with a gorgeous beach. Astoria is more of a real town, with great history (2 nearby Lewis and Clark sites, the Astoria Column and the Maritime Museum). I really like the Cannery Pier Hotel if you want to stay overnight.
Portland is known for food, coffee, beer, and wine. (and weed) EaterPDX keeps up on more of the restaurant happenings. I like the downtown cultural district with the art museum, symphony and historical society. The Chinese Garden is cool, and the Japanese Garden has been recently renovated. Walking around NW 23rd or SE Hawthorne is a good way to get a feel of more normal life, also going to an eastside restaurant. The eastside esplanade, walking from our science museum, OMSI, is lovely.