We've taken food from the F&W booths back to our room at BWV. The booths don't have "to go" containers but they will give you a second paper tray (the same one they use to serve the food) that you can use as a loose cover. It was a bit of a challenge to keep the "lid" on as we made our way through the crowd but we managed to get everything back to BWV. Real containers with proper lids and a flat bottomed bag to transport them would have made this easier but we managed. And don't worry -- no one will ask you for an explanation as to why you want to take some of the food home instead of eating it in the park. There is no reason to be embarrassed. I think it's a nice thing to do for your grandmother.