Bruce -
I think we are on the same cruise. We booked through Regent air and they routed us from SFO to SEA on Alaska in first class and then from SEA to KEF on Icelandair. For us that was better than other options which were flights to the east coast - Newark, Boston, Dulles, etc. -and a change of planes there as that would involve two shorter flights. The SEA to KEF flight is 7 hours and 25 minutes so we can at least hope to get a few winks. You are right that the other option would be LAX to a European destination - London, Amsterdam, Frankfurt, etc. - with a connection essentially backward to KEF. That routing will generate more seat miles and lots more time in the air. There is a routing LAX to SEA on Alaska that connects to the Icelandair flight to KEF.