Everyone needs to go through security at the main entrance for Epcot no matter how you get there. It is a long walk from security to the race area and about a mile walk from the race area to the corrals. There is usually a hard close for corral A at 4:30am because they are moved to the start line. Corral B is closed not long after.
You can certainly ride-share, but just be aware that the later you leave the resort will mean an increase in traffic. Buena Vista drive, the exit to World Drive and World Drive itself often become a parking lot. Ride-share, passenger drop off and the buses both take an immediate right after going through the Epcot toll booth so make sure the driver is aware of that.