For those three days...
One thing I would think is that you guys should check out staying onsite as you do the math for how much it will cost ya.
For example - at some points during the year it is cheaper for me to stay at a value resort, use Disney transportation (saves me in car rental) and I can take the Magical Express back to the airport. It also allows a family to split up easily because one or two family members can just hop on the bus to get back to the resort. As a plus, it is also "Disney" happy and you will probably need some Disney happy after your GKTW part - it is sad to leave GKTW.
But, if you are looking for a spot off site - you may be able to find a great deal...Check
www.mousesavers.com - they usually have good deals as you closer to the day. Some of the deals include breakfast and you can get a suite style room for less than a hundred dollars a night.
I also highly recommend
www.tripadvisor.com - they rank hotels and you can find a cheap one that regular people rank and comment on to stay in.
One thing I am wondering, though, is what are you planning to do those 3 days? For example...are you planning to stretch out your free tickets to the point that they will last you the whole time? GKTW can get more free tickets to things like the Space Station, Gatorland, and maybe the water parks...if you wanted to try to get more stuff in...OR are you planning on adding Disney days?