I was able to price out BOS-JFK-LAX-PHX-DFW-PEK-ORD-PHX-ORD-BOS for around $628.
That's 21.5k miles and 2.9 CPM. It seems to be a lot easier to route the PEK flights all over the place than the HKG ones, although HKG itself will automatically generate a few more miles. I was able to route the PEK flights easily through MIA or SEA or LAX, then onto DFW/ORD for the flight to PEK - HKG wasn't as easy, particularly the $504 fares.