http://www.unitedairlines.co.jp/jsp/..._fares_usa.jsp

not sure if it's cheaper for you to get from where you are to Japan and then use the "go" fare. For 20,000yen more, you can add the roundtrip transcon. AFAIK, you can't do LAX-JFK-SFO (PS service) in the same day any more ......

pm me if you need more info on the GO fare.