Alas, northbound afternoon Sounder options are very limited, only two per weekday, at 5:04 PM and 5:39 PM. And I wouldn't have been able to catch one until about 6:00 PM.
No matter, I rode the King County Metro #150 bus from Tukwila instead, which is actually a more convenient option (except that it lacks Wi-Fi) since it continues up through downtown rather than stopping at King Street Station, south of downtown.
While riding all three commuter transit options available to Seattleites into and out of our fair city would have been fun, it would also have been a "Quat Trick" for alternative transit when my use of the bike on the same trip was considered.
Anyone else ever ride the bus, light rail, and Sounder on the same commute day?