I second PokPok. I think Alberta Street in NE Portland, between 15th and 25th (roughly) is an excellent slice of Portland life. Salt and Straw, near 21st on Alberta, is another big Portland thing - it's gourmet and unusual ice cream.
If you like planned city parks, Laurelhurst Park is a gorgeous place to spend some time. You can take a stroll, have a picnic, watch people, watch dogs. . . (from Wikipedia:)
Laurelhurst Park is a city park in the neighborhood of Laurelhurst in Portland, Oregon. The 26.81-acre (10.85 ha) park was acquired in 1909 from the estate of former Portland mayor William S. Ladd. The City of Portland purchased the land in 1911, and the following year park superintendent Emanuel Mische designed the park in accordance with the Olmsted Plan.
In 1919, the Pacific Coast Parks Association named Laurelhurst Park the "most beautiful park" on the West Coast, and in February 2001 it was the first city park ever to be listed on the National Register of Historic Places.
So, the trees planted for this park are now over a hundred years old. If you like lovely old houses, the homes around and especially to the north of Laurelhurst Park are very nice.
One great thing about Portland is the bike system. There are neighborhood greenways - city streets that are set up as bike "highways." They get priority over cross streets (no stop signs) and when they cross busy car streets, there are special crosswalks and buttons you can push that STOP the cars pretty quickly.
There's a bike share system, so you can rent a bike easily. I do recommend some biking.