The itinerary for my first (and only) trip to Hokkaido is here on blog if you're interested. Rough outline:

Sapporo - Mt Moiwa, morning markets, genghis khan
Otaru & Cape Kamui
Furano, Biei, Sounkyou Onsen, Asahikawa
Jozankei/Hoheikyou Dam, Noboribetsu,
Hakodate

Of the list, in July ... I think I might not bother with Hoheikyou Dam as it's really pretty during autumn, but not so much in summer.
Also, "active" is a bit ambiguous but if you mean you like to take walks and hikes, there's quite a bit of that to be done in both Sounkyou Onsen / Asahidake Onsen and Noboribetsu.