The route can be changed according to weather, but this is going to be a counter clock wise tour, staying first 2 nights in Portland, final night in Yakima.
Meet and leave around 8 in Blaine, though I'll arrive early enough to have a breakfast there. Continue south mostly on I-5 / I-405, then keep going south by east of Mt. St. Helens via Randal, then Carson. Ride east along backroads near Columbia River. The daytime is getting shorter, we may shortcut by going through Cougar, backroads in Battleground, then Portland.
Have a morning short ride around Portland. In the afternoon to evening, lots of beer and food at Polish Festival:
I haven't done MacKenzie Pass this year, so this is going to be a must today. We'll ride through Estacada, Detroit, MacKenzie Pass, Sisters. Probably staying in Bend.
Continue east, there are some good choices that part of OR and ID. Probably staying anywhere central ID.
Start heading west, going through backroads of SE Washington. Will stay in Yakima for our final night.
Head west, through Chinook Pass, ride roads in Mt. Rainier Nat'l Park. Then home via mostly freeway.