MK is the one park that most people agree that it's better to take the bus, rather than drive. You have to walk to your car at your resort, then drive to the TTC. Park the car, walk to the tram, wait for the tram, get on, ride to the drop off area (or you can try walking right there vs taking the tram), then wait for either the ferry or monorail to come and then over to MK. It's not quick.
I would always recommend taking the bus to MK. It truly isn't that long. Yes, you 'could' have a wait of 20 mins if the MK bus is just pulling away, but I've arrived at the bus stop, just at that moment, several times and not had a wait of more than 10 mins before the next bus came along...especially for park opening hours. Take the bus...it's much easier.