There was a lot of discussion about the possibility of an LAX-GUM direct flight before and right around the time of the merger. The prior discussion is found online in the pmCO forum as "LAX-GUM 777 Service"

I'm surprised the 777 couldn't make the LAX-GUM because I thought the distance was roughly the same as LAX-NRT.

Regardless, I think the discussion of this route was put on hold when the realignment of Marines went into limbo. This year's defense bill lifts restrictions on funds and major construction will really get going in the next few years. I think UA was serious about direct service because they had that flight prior to 9/11. Once more contractors get engaged in the build-up I think they'll see the traffic and not to mention traffic from Pendleton. I would expect them to look to the 787 though because of load factors etc....