The drive from the airport is about 30 minutes. Most of it is incredibly boring and incredibly expensive on the tollway. Take lots of $1 bills or quarters.
As for the drive between Epcot and MK, it can take a while. They aren't far apart, but they aren't a hop, skip and a jump either. It shouldn't take TOO long...10-15 minutes from parking lot to parking lot. Going from Epcot to the car and the car to the transportation center to the park...that's the bulk of the time between the parks.