If I were CEO of United, I would make either GUM or SPN as Pacific Hub. Locate a lot of 757-222 to the Pacific Hub, and use it for the traffic between East Asia and Oceania.

These would be good routes.
GUM/SPN-NRT
GUM/SPN-NGO
GUM/SPN-KIX
GUM/SPN-ICN
GUM/SPN-PEK
GUM/SPN-PVG
GUM/SPN-SYD
GUM/SPN-MEL
GUM/SPN-BNE
GUM/SPN-AKL
GUM/SPN-CHC

I also would make HNL a Hawaiian Hub, and place 737-X22 at there. Then make some inter-island routes.

Seriously I'm very curious why U.S. carriers don't utilize GUM or SPN for traffics between East Asia and Oceania.