I would do this too. I even thought about it after a several of the local restaurants went under for various reasons. Keep the menu simple with core items you can work with in multiple ways. A few breakfast items: waffles, pancakes, eggs, hash browns, sausage, & bacon. Then the common fast food items: burgers, hot dogs, brats, polish sausage, fries, & traditional toppings. I would carry quality dinosaur chicken nuggets for kids. Salted pretzels, nachos, tatter-tots, & rice crispy treats would be the only additional items. With the burgers you can just offer versions with more patties. You can do a "double dog" with two hot dogs or brats in a foot-long bun.  All burgers and hot dogs would have the choice of a pretzel bun upgrade.