The scenery is amazing. Portland is fresher and greener than anywhere I've been in my life. Driving around on the back curvy roads and watching the scenery passing by was an experience in itself.
The Columbia Gorge Vista House. It's been there since the 1900's and provides a gorgeous view of the Columbia Gorge.
Multnomah Falls was extremely beautiful, but a little crowded. If crowds aren't your thing, you may want to check out some of the other falls nearby. Not as large, but just as beautiful.
Portland's minor league baseball team (The Beavers) play at PGE Park downtown -- it was cheap to go, and lots of fun on a beautiful afternoon.
If you are a Goonies fan, a trip to Cannon Beach and Astoria is a must. It's 70 miles to Cannon Beach from Portland and then 30 miles north is Astoria. Do a search on the internet to find the specific locations.
Quick Tips:
Even in the summer, bring a jacket everywhere you go -- it gets cold at night!
The best food in Portland is supposedly Thai and Japanese food. We didn't get to try any while we were there, but I wished we had!
There are lots of "unique" Portland restaurants. I didn't see a lot of chain restaurants. I don't even remember seeing a McDonald's! So, you should have plenty of options for meals. When in doubt, stop by one of the McMenamin's restaurants, located all over the Portland area.
Best Way To Get Around:
We were visiting a friend, so we had a personal chaffeur everywhere we went. Having a car seemed to be a must. He lives about 20 miles from Downtown Portland, so we were constantly driving. Multnomah Falls and the Columbia Gorge are about 30 miles outside of Portland.
Parking was a little difficult downtown. We had to search for parking spots on the street most of the time, or pay -3 to park. Some of the nicer restaurants have valet parking. PGE Park does not have parking. But once you are downtown and parked, walking is fairly easy.
Since the winter conditions are pretty bad (snow, rain, etc), road construction is done during the summers. They don't care that it's a holiday weekend, or rush hour -- the road is closed!
Most freeways have "grooves" worn in the road because of people driving on them with snow chains (which are never necessary in the winter unless you go in the mountains -- according to my friend that lives there).
A lot of the roads and freeways are very curvy -- be careful, especially in the rain.