Planning a 10 days trip to Hokkaido

Hey guys we are planning a 10 days trip to Hokkaido from Singapore.

Is it practical if we take the bullet train from Tokyo up to Hokkaido? is there any alternative?

and any recommendations to where to go? because there's alot of things to do and see. But we need some idea.

Some suggestions on where to go and access details:
http://www.japan-guide.com/e/e1101.html

Access details depend on where in Hokkaido you want to go. Flying there is generally the best way to go, but trains are a slower alternative, especially for visiting southern Hokkaido.

For example, here are access details for Sapporo:
http://www.japan-guide.com/e/e5306.html