We are having a meat tray for sandwiches and my beans and weeners. I need to know how many gallons or quarts to supply. I was figuring on 18 quarts. Is that close?

18 quarts- 1 Nesco roaster- is only a little over 4 gallons. You don't say how much Sandwich materials or what kind, or what side dishes, but for BBQ typoe psrties, I usually figure 1 gallon of side dishes- beans, potato salad, etc, for each 10-12 people. I would suggest about double what you are considering, if it is the main dish. You can figure 1 #10 tin can hold 25 servings, so with that many kids, 4 cans might be enough if you have other sides like slaw, potato salad, etc, but then you need to add the weiners.