I have gone N to S once in entirety and otherwise two to half a dozen times in most parts. Good weather brings prevailing winds off the coast and north. While there can be days with light/no wind, I agree going this direction would be a grind...

If it were me and I wanted to arrive by bike, I would go N to S from Seattle to Tijuana followed by the Amtrak trains from San Diego to Vancouver and then cycle into Vancouver to meet the family.

I left Vancouver the US Memorial day and over next week had one day with heavier rains and two days with showers. On a different trip leaving Portland mid-May had a day with torrential rain near Brookings. So prepare for possibility of wet but not all the time.