The easiest way to get to Hakuba from Narita airport is to take the shared Chuo taxi. The 15,900 yen per person service will take you door to door from Narita or Haneda airport to you accommodation in Hakuba. No transfers, and no bags to lug around up and down the train station stairs. To make a reservation you will need to fill in a form at least 48 hours ahead of time. You can find the form, and more details here.