7 or 14 day JR rail pass!!!

Hi there

I was wondering what rail pass would be better value for a 16 night Japan Trip in June. A 7 day pass or a 14 day pass?

Currently I have the following planned:
- Tokyo - 4 nights - fly into Hedena and out of Narita. - Flight booked Tokyo to Sapporo - 3 nights in Sapporo with day trips in Hokkaido - Flight booked to Osaka with 3 nights in Kyoto - 6 remaining night before flying out of Narita Airport and options to spend that time include, Osaka exploring, Hiroshima day trip, heading back to Tokyo via Mt Fuji, or heading back to Tokyo via the Nagano region. I would welcome advise on how to best use the remaining six days also :).

From my research, the following is the highly likely JR rail use:
- Hedena to Tokyo one way - Tokyo to Narita return - Sapporo Airport to Sapporo Central Station return. - Sapporo Central to Otaru return. - Sapporo Central to Furano return. - Osaka Airport to Kyoto Central - Osaka to Tokyo.

Potential use:
- Osaka to Tokyo via Mt Fuji, or via Nagano - Osaka to Hiroshima return. - Around Tokyo and Kyoto where applicable

Look forward to hearing back.

Justin