I just returned from a 7 day cruise on the Magic. I had rented a car from Budget at the airport and returned it at cocoa Bch and used their shuttle to get to port. Here is how it worked for us with no problems.
Left MCO Hyatt at 9:00am. Arrived at port about 10:00am, there was a line to gain access to the terminal drop off already, we were about the 5th car in line.
At about 10:15am they opened up the gate, checked id's. They were very nice, Could pull up with car at luggage drop off. At the gate security, they recommend that you give your docks, photo id, charge card if possible to spouse so she can check you in, You must keep some form of photo id to get back into port terminal. I had both Driver's License and Passport so duplicate Id was not a problem. Charge card was already noted on car charge record so didn't need that also.
Dropped family off along with luggage, then drove out of terminal area, to gas station near Budget drop. Filled up car. Drove the block down A1A and into car return. Parked car, took mileage and went inside. Was out of return in less than 5 minutes. They had a van shuttle to return me back to terminal. You are dropped across the street from terminal building. You walk across street, have photo Id checked again against cruise list and allowed into terminal area. Go thru, xray and metal detector up the stairs and there you are.
I met my wife in terminal. She had already checked in, just had to go to CM where wife had checked in, show photo id and was handed kttw card. They were already inline. We were about 15th family in line.
Whole procedure was very simple and will do it again this way for our next cruise in Nov 05.
Just so you know, there were other DIS members coming from the Raddison using their shuttle and also limo service and they were all being dropped off across the street at shuttle drop of point with no problem. There is a white tent set up in the parking lot where this takes place. This is also the place where you are picked up if you are being picked up by outside (non disney) shuttle services.
Hope this helps.
Kennyk