We normally put the cruise in the middle of our vacation, especially coming from the other side of the world, too many things can go wrong otherwise. We normally do 3-wks total, with a week or so either side of the cruise, depending on cruise length. I could not arrive the morning of the cruise as I would be too anxious that we missed it for some reason.
As for getting to the port, I think it very much depends on what is your priority and whether you want to be early or not. Previous cruises, we have car hired down and then once returned to rental service before cruise, and once just paid for car hire and car park and left it parked in the parking garage. That was a short cruise, and we got a discount for extended car rental period. This time, because we are on a 7-nighter, we are still trying to work out whether we will do one-day car hire and drive ourselves, or book a private transfer.
If timing doesn't matter, then go with the
DCL transfer ($35 per person, one way). They will pick you up from the airport or a WDW resort and deliver you to the port hassle free. The only catch is resort pick-ups don't tend to get to the port until later in the check-in/boarding process. The advantage to that is you generally get off the bus, go in through security, check-in without too much wait and board straight away.
If you want to be there early, then you can do private transfer or car hire. Both are problematic in their own ways. For two people, a private transfer will be very expensive; they start around the $150 one way mark, depending on company and vehicle size, whereas a one-day car rental is most likely to be cheaper. However, the car rental locations are not at the port, they are just outside. So, you can either drop your partner and luggage at the port and go to car rental location, or just go straight there together. Since there are just two of you, that should be reasonably easy to deal with. Each car rental location has a shuttle bus which will run you back over to the port once your car is dropped off. The shuttles tend to be shared between two or three car companies so will load in multiple locations, and/or you have to wait to board if the car rental locations are busy because lots of ships are departing the same morning.
Hope that helps a bit!
