i say shanghai. u can do a day trip to hangzhou afterwards...only few hours away from shanghai ...great scenery

One option if your family includes nature/animal lovers is to get a connecting flight to Chengdu then drive up to Wolong Panda Reserve.

You could spend a night in Chengdu, drive up to Wolong (about 5 hours over mainly bad roads), visit the pandas the next day, head back to Chengdu and enjoy that laidback city before making your connection back to Hawaii via Shanghai or Beijing.

Good luck with your planning.

CanadaKate