I'd pick a transfer through HKG, also.
From PDX, you're flying PDX-YVR/SFO/LAX/NRT-HKG or PDX-YVR/SFO/LAX/NRT-PVG/PEK-SZX. Why bother with an extra stop and an extra chance for a missed connection? Even if the ferry schedules don't line up, there are plenty of buses that make the trip from HKG to Shenzhen.