We will be travelling to Niseko in February and would like to get the train for Chitose Airport to Kutchan station. Not sure of how train travel operates from Chitose - all I know is that we change trains at Otaru which then goes on to Kutchan. Can you pre book reserved seating prior to our arrival? There are 6 of us in the group with snow board bags and am concerned about not being able to get on the train