Our approach on vacations is to work out a way to eat two meals a day in the room and one meal out. We do that to save money (no particular diet for us), however it also means we can eat a bit healthier. So, for breakfasts, we will have cereals (usually Cheerios of a couple kinds) on hand, some fresh fruit (bananas, strawberries, mango, oranges), yogurt, bread, and spreads (peanut butter, jam, apple butter, houmous). You also could make a batch of pancakes and take them with you to reheat in the mornings. Bringing some quick oats will provide a good breakfast for the baby (and maybe others too). The bread and spreads provides a good option for lunch/dinner. We also bring/buy some fresh veggies (cucumbers, peppers, grape tomatoes, baby carrots) which will go well with sandwiches for the folks with teeth.
Should you feel a sudden burst of energy in the next day, you could cook a pot of an easy bean soup (lentil/etc) and take a couple plastic containers of it with you to reheat when needed. If you feel up for cooking one night, you could do pasta and a bottled sauce, make some salad, and you're set! It's only a few days. Have fun!