I don’t know the fuel range of their plane but it would have been over 2,500 miles to Honolulu. Purely speculation, but they may have been departing at night to take advantage of a lower density altitude. The plane may have been loaded such that it could not fly beyond ground affect.
“but it would have been over 2,500 miles to Honolulu”
They were probably heading to Kiribati, which is halfway between Samoa and Hawaii.