The number of miles routing through Asia should be the same as if you we're flying non-stop between SYD-SFO. Use the multi-destination tool on the UA website and use a combination of SIN, BKK, ICN, TPE, NRT, HND, and KIX as the connection points with no more than a 24 hour stop at any one connection point. Be sure to be cognizant of the dates you use since this could take an extra day of travel plus crossing over the dateline.

I was able to piece together a combination of mostly long haul F and a few C segments between LAX and SYD connecting via ICN, HND, and BKK on OZ and TG. The return is via BKK, HKG, ICN, KIX, and SFO on TG, OZ, and UA all for 160K UA MP points plus a couple hundred USD in taxes.