Here are some directions from the airport to MK that I pulled off of Mapquest. Just reverse them. Hope it helps!
DIRECTIONS DISTANCE
1: Start out going North on PARKING towards AIRPORT EXIT. 0.4 miles
2: Turn SLIGHT LEFT onto AIRPORT EXIT. 0.2 miles
3: AIRPORT EXIT becomes AIRPORT BLVD E. 0.7 miles
4: Turn SLIGHT LEFT onto FL-436 N. 0.3 miles
5: Take the SR-528-TOLL W ramp towards US-17/INTERNATIONAL DRIVE/US-441/US-92/TURNPIKE/I-4. 0.3 miles
6: Merge onto BEE LINE EXWY (Portions toll). 10.6 miles
7: Take the I-4 W exit on the left towards TAMPA/DISNEY WORLD. 0.6 miles
8: Merge onto I-4 W. 4.1 miles
9: Take the SR-536 E exit, exit number 26AB, towards EPCOT/DOWNTOWN DISNEY/ANIMAL KINGDOM. 0.2 miles
10: Keep RIGHT at the fork in the ramp. 1.0 miles
11: Merge onto EPCOT CENTER DR. 2.8 miles
12: Take the ramp towards MAGIC KINGDOM/MAGIC KINGDOM RESORTS/FORT WILDERNESS. 0.4 miles
13: Merge onto WORLD DR. 0.5 miles
TOTAL ESTIMATED TIME:
35 minutes TOTAL DISTANCE:
22.0 miles