Hi Chris. You've got a few choices up your sleeve - the two "direct" services are offered by Canadian and Canada 3000. CP will get you to HNL non stop where you will connect onto another "CP" flight to SYD, but this leg is operated by Qantas. C3000 fly you all over the place (YYZ-YVR-HNL-NAN-SYD - and that's the shorter of the two routings!) but will get you there at a normally cheaper rate. Failing that, you can use United, Air NZ and Qantas all non stop daily from LAX-SYD, UA will fly you non stop from SFO daily as well, or you can one of these two UA flights in Chicago which will involve a change in LAX or SFO on the way through.
That's a lot of miles to go begging in a Frequent Flyer scheme - your choice may come down to your scheme's partners so you can collect the miles.