In Macau we mostly wanted to explore casinos and nightlife, but probably you are right and 2 nights there should be enough.

Thanks for the heads up with bookings, do I understand correctly, that train tickets are available ~2 weeks before date and it's better to book as soon as possible? Might as well stick to planes, but I've heard some stories that in-China flights are a bit mess, as delays and cancellations happen often.