I live in the Hood River area which is about 1 hour inland from Portland on the Columbia River. So I can't answer a lot of the specific questions about Portland but I can say that you would be very hard pressed to find a nicer area to road bike and the wilderness access is amazing. The pacific crest trail runs north to south along the Cascades, about a half hour drive from Portland, I live between Mt. Hood and Mt. Adams, amazing recreation areas. There's world class windsurfing, kayaking and mt. biking in the Gorge. organized road season starts in April out here, but there are organized rides in the Portland area all year around I think.
I moved to the area from Canada and I love it.
Most of the locals I know plan on a trip some place sunny in the winter to break up the duldrums.
Living life like there's no tomorrow.
http://gorgebikefitter.com/
2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS