This got me thinking that if the OP didn't have any flights booked what is the fastest way to get silver status without either doubling back on yourself or returning?
How about an all F booking from LAX to JFK on AA (180 TPs), JFK to LHR (180), LHR to SYD (330) so that by the time you arrive in SYD you have reached Silver with 690 TPs.
Can it be done any faster?