A week is an awfully long time to stay at Sheraton Keauhou IMHO. I might suggest you instead stay at one of the resorts on the Kohola coast. Much nicer resort IMHO, especially for a weeklong stay. And with the economy in the dumps, I hear you can Priceline the Kohala Coast resorts for under $100 per night!!! Can't beat that!!
Sheraton Keauhou is fine for a 1 or 2 night stay, but any longer than that it would start to get old and you'd start to get bored I would think............unless you plan to spend almost no time at the hotel and a good amount of time driving to snorkeling south of there or the beaches north of there or the volcano or similar. Then it would be centrally located to those things and perfect for your needs.