I back from Hokkaido. I was on train most time of these travelling days. Although I am exhausted, I am feeling it is very valuable to visit Hokkaido. However, there may be some pity, for example, short walking on streets of Sapporo, Sendai, because I didn't have enough energy to go further and to back to station. Except buying souvenir and indigenous food, the cost is a little more than my budget.
I will post the detailed cost in a few days.