When traveling in Yellowstone it's always a good idea to bring along a cooler -- that way you can carry some snacks and lunch items for a picnic or break and not have to worry about making it to one of the more developed areas of the park, where there are restaurants and cafeterias. Generally you'll find burgers and sandwiches at cafeterias and full meals at restaurants. There is a good selection of entrées such as free-range beef and chicken; game meats such as elk, venison, and trout; and organic vegetables. At the several delis and general stores in the park you can purchase picnic items, snacks, and sandwiches. Reservations at all the sit-down, full-service restaurants are a must for dinner during the height of the summer season.