My wife and I did go from EPCOT to DD on a Dbus but that was about 3 or 4 years ago.
I do know that they have buses going to all points from the TTC.
But if I where you and your are going to have a car with you take the car. This is the way we do it. WE park at a resort with Valet Parking and take the monorail/motor launch to the park. Then when we want to leave we just go back to the resort where we parked and let the valet bring the car to us. It only cost the amout of the tip. It is much better, and less of a headache, for us to do it that way traveling with our young Dd.