LAX-SAN-JFK, LAX-LAS-JFK, LAX-BOS-JFK, LAX-MIA-JFK. On the MIA option, be careful as some flights are 3-class 777s; however every other day or so AA flies a 2-class 763 on the route, which would be preferable to the every-day 738s. You could also go LAX-MCO-JFK, but I think they're using ex-US A321s on the Orlando leg, meh.

I assume you want "A" for the QFF credits, but am obligated to mention that my choice would be LAX-YVR-JFK using CX's 77W on the redeye. Both segments would be in D, however. AA is running an E175 from LA to Vancouver, with pretty decent seats up front.