You stop at the convenience store in Sanford (the one popular in Pennsylvania but not named Sheetz
) and get a prepared salad/sandwich to eat right away, plus snacks, donuts, and soda to take on the train.
Unfortunately, that pesky Florida heat means you do need a cooler for the soda and probably have to give up the chocolate-covered and cream-filled donuts.
Actually, the Amtrak cafe food sounds downright nutritious after this.
Quite seriously, if I am looking at the departure/arrival times correctly, both southbound and northbound Auto trains seem to leave early evening and arrive early to mid-morning.
I’m assuming you have to wait around for a long time on either end for your car to get loaded/unloaded, so for the departure station, if there’s an air-conditioned waiting room, I would get a nice takeout meal and sit in the waiting room and eat it. Then the next morning, have coffee on the train and then stop at a diner for a substantial breakfast.
I just did a search for diners, and there seem to be a few in/near Sanford. Oddly, not much at Lorton.