I also wouldn't count on hotel shuttles.
These were the times posted at the HRH during my stay in June 2004.
http://www.nogodforme.com/images/DSC02260.JPG
As you can see, the shuttle leaves at 08:55am, just when SWF is opening. The whole key to getting on JTA and Kracken with no wait is arriving the parking lot around 08:30am.
This is why I tell everyone to rent the car. Yes, you pay for gas, parking at the HRH, and parking at SWF, but the convience makes up for it. You can save some money back by visiting the grocery store and stocking a cooler. When I'm on vacation, the rental car becomes my 2nd home. I bring the cooler in the car and have drinks/snacks to eat when I arrive/leave the park.