Keep in mind the route you described is basically the great circle route so it's the route you would take in no winds. http://www.gcmap.com/mapui?P=sfo+-+hkg
Alaska and Siberia are still a bit off from the SFO-HKG great circle route. From closest point there is about 1500 km to the Siberian mainland (unless you count Kamchatka as Siberia, and even that is still some 500 km off so you don't really come "over" Siberia.).
But yes, it wouldn't be that much a detour to go nearer Alaska and over Kamchatka.
