I"m doing LAX-nw-NRT-nw-BKK-emirates (EK)-SYD with the same return. I stopover in BKK for a few days to see a friend. It was $668 for the NW portion and $700 for the Emirates portion, which isnt too bad. The EK flights leave in the evening at 6-7 PM. Makes for a forced overnight (18 hours) going to SYD but not bad for the return arriving 1 AM into BKK with the NW flight leaving at 6 AM. I'll let you know how it all works out in May.

You could post all the miles to CO and get lots of EQM and miles on the whole routing. If only I knew I was going to to this at the beginning of the year....