pdxduck

I just moved out of Oregon after living in Portland for 28 years.
Do not stay at the mountain. It is a short enough drive from Portland that you will be fine. Multnomah falls is very nice and right off I-84 heading out to the Gorge.
I would stop off at Multnomah falls then head out to Hood River. You can look around that town for a little bit and maybe check out some wineries or breweries in the town and then head to Mt. Hood from there.
When you are in Portland you want to check out certain neighborhoods not just downtown. Division st, Alberta, Mississippi and Hawthorne are the main ones to go see.
Take your wife to Salt an Straw for Ice cream and make sure to try all the regular flavors. Dont be shy to ask for more samples, they wont care.
If you want to take her somewhere cool in the city for a drink, go to Portland City Grill and have a drink where you can overlook the city from the 30th floor. Or you can go to the Departure on top of the Nines hotel.
Another popular attraction is going to "Hubers" and ordering a spanish coffee. It is the oldest bar in Portland and its a lot of fun. I prefer the iced version.
King Estate Winery is a lot of fun. It would take you probably 2.5 hours to get there from Portland.

There is lots of fun places to visit in the area just dont settle for any chain restaurants or anything because there is so many good places to choose from.

p.s. dont go to voodoo donuts. Its not that good and you will be dissapointed. If you want a cool local donut place go to PIPS Donuts or Blue Star.