Get a quality cooler. Make and freeze some soup in mason jars and use them as ice packs in the cooler (works with other frozen meals as well). You can even just freeze water. Pack sandwiches, hard cheeses, fruit, yogurt, ready to eat oatmeal in the cooler. You can also bring nuts, granola, etc. Eat in order of perishability. Most hotels have a mini fridge and even a microwave in the room.