I am in the same boat as you are. I am looking for a 11 day rental and it is something $375-$400 depending on the agency. And that includes the codes!
Just for fun, I tried looking about the same time period in June. The amount was only $205! So I am hoping that the closer we get, the lower the prices are. For now, I rented one week only and will return the car after a week at the car care center. I will probably rent a car for the return trip to the airport or take the shuttle. Not sure, hoping the prices go down as we get closer so I can just rent for the whole stay. Of course ,I will be watching for the rates as we get closer to the date.