Orlando Lynx is public transportation (google orlando lynx) but I don't know if they will have buses running that time of the morning - 3 AM, read the Disney recommendations on time. Mears runs service as well. Those can get you to Disney World but maybe not to Epcot where the race starts. Maybe your hotel will run a shuttle. You could drive but traffic is a mess. Figure a minimum of an hour to drive and park - probably longer. All of which begs the question - Is there a reason you're not staying onsite?