The Hyatt Regency is also attached to Tochomae Station (Oedo Line) via a comfortably heated underground passage.

Getting to the hotel from NRT, the limousine bus is the easiest. They also have a discounted ticket if you purchase with your Discover Card at NRT.

Once you're checked in, you can either put yourself at the mercy of the shuttle bus to Shinjuku or walk 5 minutes downstairs to Tochomae station.

Best of all, as you come up the escalator to the hotel, there's a shiny and nice 7-11. ^