I'm in the same situation as you. You might want to get round trip as you may already know about how some schools may try to cheat you out of the year end bonus/airline reimbursement by making up a student complaint against you, etc.

I currently use AA and UA and fly into PEK. I've used BA but now find that useless for me after getting one free trip from that card. I didn't realize you can use US Air to get to China.

I last used United (actually CO) miles to go Asiana/Singapore Air codeshare from LAX > Seoul > DLC and I think I used 92.5k for business one way and coach back. The codeshare on United is a good deal for that type of travel.