When you are in a hurry and only have an item or two, a self-checkout option would be a great feature at Sheetz stores. You can pay for MTO orders and scan UPC's of other items at the kiosk. Once you're done, swipe your My Sheetz Card, swipe your credit card to pay, and you are on your way out the door.
To handle paying for gas inside, if you swipe your My Sheetz Card at the pump and you have an unpaid transaction at one of the pumps, it can automatically add the gas purchase to your order once you swipe your My Sheetz Card at the kiosk.
The MTO ordering kiosks could probably serve this purpose... they would only need a credit card swipe and a barcode scanner. The system could be modified for a "register" mode and "MTO" mode. Once you are finished ordering your MTO, you could be presented with an option to checkout, as well.