You'll just miss BMW/Porsche track day the 25th.
There's some nice coast scenery and fun driving along 101, being from Hawaii I would imagine you have seen the ocean though.
Long Beach in Washington is nice. In Oregon there's Cannon Beach, Yachats, Nehalem, Aquarium in Newport, Tillamook for the cheese factory (free cheese curd samples) and ice cream, a couple of casinos (one in Lincoln City). Hug point has 1 or 2 cold, dark caves that may or may not be romantic.
Only B&B I have stayed at is Arch Cape below Cannon Beach,
http://www.archcapehouse.com/, a bit pricey but very nice, great breakfast and cool rooms. Inn at Cannon Beach has some nice rooms too though as I believe thay have 3 locations.
In Portland try NW 23rd Ave or SE Hawthorne for a variety of restaurants and shops.
Have a good time and holler at any of us if you guys want to hit a restaurant, coffe shop, pool hall.....