Boston AA-Flyer has the best idea, and then you can hit HKG on the way back. However, if you decide to go the Cathay route as long as you can get them as AA code share you can earn full AA miles (just no upgrades)

Bangkok Airways is also a cheap way to get into HKT. However if you status on any AA airline get United or BMI or another *A to match so if you fly TG you can get lounge access, priority check-in and what not.