In summer season, the busiest period is mid August. This period is called “Obon (お盆)”. Everybody try to go back to hometown in this period. In this year 2012, August 10 to 19 will be Obon period. Especially the direction to go out from major cities on Aug 10-12 and the direction to go into major cities on Aug 17-19 will be much busier. These dates are weekend days. Everybody will try to move on these dates. If you travel in this period, try to go opposite direction. It makes you to travel much easier.
Furano Lavender Express (フラノラベンダーエクスプレス) and Furano Koyo Express (フラノ紅葉エクスプレス) are limited express trains to Furano (富良野) directly from Sapporo (札幌). These trains can be used by Japan Rail Pass with no extra charge. Furano is one of very popular spot in Hokkaido for the tourists. These trains are the seasonal operation trains because the lavender season in summer time and the fall color leaves in September are busy periods. So when you build your itinerary, please check the latest operation date before you put this train in your plan.