visiting Hokkaido area

I am planning to visit with my daughter Hokkaido area for 6 days at the end of September. We have not decided yet if we will rent a car or use the public transportation to tour around the parks.

We are planning to go first to Daisetsuzan National Park since it is highly recommended during the fall.
Since our time is limited, can you recommend on the best parks to visit beside Daisetsuzan Park during the farm our visit.

Can we do this with public trasportation?

http://www.japan-guide.com/e/e6775.html

Thank you for the link. I am planing to visit this park. I wanted to know if it will be posile to visit other parks in the time fram of 6 days using public transportation.

The latter half of Sept is indeed a very good time for autumn foliage in the Daisetsuzan National Park. 2 very popular koyo sites there are Ginsendai and Daisetsu Kogen Onsen.
http://ramblingonmyhokkaido.blog112.fc2.com/blog-entry-77.html
http://ramblingonmyhokkaido.blog112.fc2.com/blog-entry-95.html

If you are going there using public transport is not a bad idea as you can�ft drive directly to those places. Use Sounkyo as your base where there is shuttle connection to both Ginsendai and Daisetsu Kogen Onsen.

For the rest of the trip consider visiting Asahikawa, Biei/Furano and of course Sapporo and Otaru. How to allocate the time for a short 6 days visit really depends on your own preferences and you may need to skip some sites for a less rushed itinerary.