Train Travel to Sahoro
From either New Chitose Airport or Sapporo City, you can catch the train to Shintoku station. From the airport, catch the Chitose Line to Minami Chitose Station, and then transfer trains onto the Sekisho Line. The trip from the airport to Minami Chitose is only around five minutes, and then Minami Chitose Station to Shintoku will take around two and a half hours and cost approximately 4,820 yen. From Shintoku station, a bus or taxi will take around 15 minutes. A bus will set you back around 510 yen for adults and 260 yen for children, and a taxi will cost around 3,000 yen.
Search Japan's train schedules here: HyperDia
Japan Rail Pass: For travellers visiting cities either side of the ski resort stay, a Japan Rail Pass is a fantastic investment, allowing unlimited train travel on most Japan Rail trains, for periods of 7, 14 or 21 days to suit your travel schedule.