It sounds like you will have to add an extra $4.00 to the dining budget for each restaurant meal to keep the kids happy. Could the adults drink water instead of ordering a beverage or have the adults share some meals during the trip to cover the added cost of the milk? You could also skip some meals in restaurants, buy groceries and bring your own meals to the parks or eat in your room. If you don't have a car you could order groceries from a delivery service or take a bus/taxi/uber/walk to a nearby convenience store, grocery store, Target or Walmart to buy essentials.