tini & gerlie... yes, tai wai is miles away from tung chung. the great thing about tung chung, though is that it is so close to the airport, there are lots of buses that pass through....
i'm sure you two can find a bus that runs between tai wai and tung chung.
as for gerlie, there are LOADS of folks in db, jump on the bus to discovery bay for an afternoon at the plaza. i guarantee you there will be other kids around (especially after 3pm). you can sit and enjoy a coffee while your little one meets some friends.