That would depend, are you doing two one way rentals? If so, that would require you to rent from a company with a location in cape canaveral. It would also depend on what kind of booking discounts you can find, and ultimatly the price, milage included, and comfort with the company.
I personally chose Budget, round trip, because it wound up (even with parking) coming in just a hair more for the week, but that convienience of walking off the ship and to the car is worth that difference to me