I really love your question!  I live in the Willamette Valley but have a loft in the Pearl District in Portland. The main thing you have to do in Portland is EAT!!!  Take advantage of one of the many great walking tours of the city.

From Portland, I would travel to and through the Willamette Valley on Highway 99W.  Staying off the interstate will give you the best experience.  Wineries are everywhere as well as the most beautiful B & B’s.
Check out www.obbg.org and use the interactive map to locate a B & B in wine country that  suites you.

There is a lot to see in the valley but our wineries are our main attractions as they should be.  Each one is unique and beautiful with qualities not found anywhere else.  A few of my favs:  Left Coast
Cellars, Van Duzer, Airlie Winery, Sokol Blosser and Adelsheim.   I also recently toured our Oregon Olive Mill in Dayton.  This place is great.  They give tours, offer olive oil tasting, shopping for edible items as well as locally made products, wine tasting and the views are pretty nice too!

A stop near McMinnville at the Evergreen Aviation and Space Museum should be on your list as well.  The Spruce Goose is housed here as well as many other very cool planes and space vehicles.  Totally worth the stop.

My biggest piece of advice is just to take your time when driving through the Willamette Valley.  Take a side road or two and you may be very happily surprised at what you find.  It’s a beautiful place so
enjoy it!