Hi, I'm hoping to take the Hamanasu night train from Sapporo to Aomori. I understand that I can try to reserve a seat in the Carpet car or Dream car without incurring extra charges if I have a JR Pass. The problem is that we only arrive in Japan about 3 days before this leg of the trip. Do you know how difficult it is to reserve those types of seats for a Monday night in mid May? Do you think we'll have trouble getting a reserved seat if we only reserve 3 days in advance? If those seats are not available, is it usually easy to get a regular seat? Thanks.