Have two limited time bistro style sandwiches available per month. Example, a turkey pesto caprese sandwich on multigrain bread and a vegan option like a beet and lentil burger topped with apple slices, sauerkraut and Dijon mustard on rye bread. I think the veg option is important and if well advertised will draw in a lot of customers.
Sell Limited Edition Collectible Holiday Sheetz branded toy trucks that match the style and build quality of the toy trucks sold by that green colored gas station. They would command a premium price point, sell out fast with Sheetz Freakz and make the brand a part of people's holiday memories.