Depends on which park you are headed to and the time of day. There's a back route to MK---from CP go out to the main stoplight, turn left, then right at the next stoplight. Turn left at the light on Vista Road. You will end up driving past Ft. Wilderness and out to the loop where the monorail hotels are located. Turn right (it's one way), turn left at the next light, turn left when it dead ends and then look for the place to turn back into the MK parking lot (left). If you get to Hess you went too far and will have to loop back around via a u-turn.
For Epcot and MGM it's fastest to jump on the freeway and take the the next exit to get there. AK is another exit further down I believe. For DTD I like to take the road into the downtown Disney area, which is the right turn at the light before the freeway entrance.