I would pick the W too, if the amount of points need does not put you off (20,000 per night!).

Even with a baby, I don't think it's that hard from the Airport Express, through the mall and then to the W. There are elevators and then it's flat all the way to the lobby. Just look up for the signs that say either Ritz Carlton or W.

A few hours before, maybe one of you can go down to the station and check all your bags in, that way, you'll just have your carry-ons and baby stuff to take to the airport. Cannot be more convenient!