I think you need to do your homework. Each retailer may want somthing different so you cannot make an offer until you know what the goals of the retailer are. You should set up a meeting to find out what a retailer may find as an advantage or disadvantage to having a vendor in the parking lot. You also need to find out what past experiences they may have had in the with food vendors, personal and professional. Once you do this you may have a better idea of how to proceed.