I began my journey to Hokkaido by taking an 8-hour Shinkansen (bullet train) from Ueno. 

The itinerary was to start off from the southern part of Hokkaido, moving up to the central and subsequently taking a loop to the Eastern portion before returning to the central part again. 

My journey in Hokkaido ended with a 12-hour night train back to Tokyo, transferring to a few different trains along the way. The train ride was rather enduring but this is the budget way as the JR Pass could be fully utilised.