From the Key West resort, take Epcot Center Drive to I-4, then continue as Bob indicated above. We also agree you should keep track of where you park as all levels of the parking garages at Universal look the same - we always take a photo of the level and area where we parked so we can easily get back to our car at the end of the day.
Keep in mind the time estimates provided by Bob will also vary dependent on traffic on I-4.