To answer your question...your itinerary is "doable", but I don't know how enjoyable it would be rushing through everything. I agree that 2 days on the Big Island is way too short. I was there for 3 days and needed more time. It's almost an 3 hour drive to get to Volcano Park from Waikoloa Village. Hawaii is about relaxing and taking it easy.

You also should try Parasailing on Big Island. I used UFO Parasail in Kailua-Kona.