You could fly into NGO (Nagoya) and the bus/train would be cheaper, R/T around $120, around $180 from NRT. see this site for routes/prices
Japan train route finder. If all you are doing is Hakuba (Hakubaiwatake Ski Area) then its cheaper than the rail pass. A quick search of rail passes does not show a 5 day pass, only 7,14 &21 days. 7 day is $244.
Just things to look into.