We often split CS meals, maybe 3 meals for the 4 of us, depending on what we get. We don't buy drinks, we bring hydroflask water bottles and refill them as needed.
We stayed offsite for the first time last June and a couple days we brought a cooler with deli ham, cheese, chicken salad, oranges, grapes, carrots and water and left it in the car. When we were ready for lunch, we walked out to the car, made sandwiches and had a quick lunch. I probably wouldn't do it at MK, we were at HS those days. We didn't do it every day.
If you are going back to the condo at any point during the day, eat then. You don't have to cook a big meal, just something easy. We did a frozen lasagna one night for dinner, and put buffalo chicken in the crockpot another day for a late lunch/early dinner. Even if you get a rotisserie chicken and some pre-made sides from the deli at the grocery store, it will be less expensive than park food.