Yes, but unless you were touring your way up there, it would be crazy. You can fly up there in about 2 hours, and there are dirt cheap airfares on low cost carriers like Jet Star or Peach, or ANA's Experience Japan Fare. Some are as low as ¥4800 (about US$ 43) one way! http://www.jetstar.com/jp/en/home http://www.flypeach.com/pc/en http://ana.ms/20Xtf8t
You can ride on any JR rail lines. But even from Tokyo to Hokkaido, using the bullet train as far as you can go, it would take over 8 hours, completely killing the day for you. It is a very long way by land travel. By plane you'd be there in 90 minutes. But it's your choice.
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http://www.jetstar.com/jp/en/home
http://www.flypeach.com/pc/en
http://ana.ms/20Xtf8t
But it's your choice.