Here is the itinerary.
BOS to PVC (14 July -> 15 July, via EWR)
PVC to NRT (17 July)
NRT to GUM (18 July)
GUM to BOS (July 19, via HNL and SFO).
This meets the letter of the 144 hour transit and we'll be staying 2 nights in a Shanghai hotel. (And then one night in Tokyo and one night in Guam).