Ah, the 591/592 rotation.
Sixteen, or was it a 14 day trip.
All the way to Melbourne via JFK, LAX, HNL, NAN (Nandi, Fiji), SYD and back.
Did several of those in the early 70s.
Remember being the nav on a delayed flight - between NAN and HNL having a meridian passage - look it up, a navigators dream - better than sex!!