transpac

I think departing UA passengers are likely to have use of one or more of the following lounges (on level 3, one level down from check-in, one level up from the boarding gates) based on status, CoS, etc.:

Royal Silk Lounge (Concourse D, Garden View) (*G/RCC/1P/1K/F/C)
Royal Silk Lounge (Concourse C, Airside View) (*G/RCC/1P/1K/F/C)
Royal First Lounge (Concourse D, Garden View) (if in UA first, and if open at the early hours)

This is just my guess based an an assumption that the UA flight wil depart from Concourse C (gates C1=C10). The Concourse D lounges referenced above are close to the C Concourse.

I fly out later this week so will attempt to check as much out as possible and post here.