I've read a little about in-town check-in in Hong Kong, even a day early. I understand that this requires one to be an Airport Express train passenger. Does it work this way: if you check in a day early, they take the train fare from the Octopus card, and it's programmed not to take the fare again when you take the train the next day? Is there any extra fare for the three single bus rides between hotel and station (round trip the day of check-in, and one trip the day of departure)? I'd be eligible for this, taking a flight to Vietnam on Cathay Pacific. My bottom line question is whether it's worthwhile to do this rather than take the A21 bus from the New World Renaissance Kowloon. The bus is cheaper, has no change of vehicles, and may be more scenic, but takes longer. Can I expect to make it in a comfortable time taking a 6 a.m. bus for a 9 a.m. departure? I'll have another HK stop on my return (Holiday Inn Golden Mile), taking NW to the U.S. at a similar time, which I understand would not be eligible for in-town check-in. Of four single airport-city trips, maybe I'd like to take one on the train to experience it. Perhaps doing in-town check-in on the day of departure, if it just needs to be done 90 minutes early, would work best; any thoughts?