As others have said, yes I-90 is the route. Wind usually not a factor. Only near the Columbia near Vantage.
From Tacoma, take Hiway 18 (Federal way area) to I-90. This will bypass 405 which goes thru Renton and Bellevue. I-90 to Spokane. Great road, especially the last 150 miles or so.
Joe in Seattle; winter: Motorcoach CC, Indio, CA
2015 Essex 4503
2010 Honda CRV toad