Hokkaido

A group of 7 family members will fly to Sapporo August 9, and will take the scenic route to Tokyo around the 16th for a couple days there before leaving Japan on the 19th.

Which pass is best for getting around part of Hokkaido and shinkansen to Tokyo? Also, based on the duration of the pass, which day should I start to use it in Sapporo so that it covers travel around Tokyo as well?