We are a family of 5 as well and drive, so this may not pertain to your family. On the drive in we have one stop at Millenia Mall and that is BJ's warehouse club that we belong to. It is convenient for us as it also has a BJ's Liquor store and BJ's gas station with one exit.
I must say that we usually go on 6 or 7 day stays and of those 3 we go to the theme parks. So at the park we usually eat our main meal of the day at lunch, so we usually make do with a snack later in the day and eat a light lunch meal for dinner back at the resort. So that leaves 3 or 4 days that we need to plan a main meal. We do take snacks into the parks (water parks we take lunch as well).
Also, we do bring spices,condiments,rice of some sort, 15 cnt package of hot dogs and pound of ground beef(frozen for travel), butter,syrup,one bag of cereal, jelly, peanut butter (got to have the last two in case we get lost

)and other things that we cannot get in small quantities at BJ's.
This is our typical shopping list/menu although it may vary with more fish for dinner than pasta:
Breafast food:
- Krusteaz variety pack(waffles,pancakes and french toast) good for 2 mornings of waffles, 1 for pancakes, 1 for FT
- Greek yogurt
- orange juice
- 1 gal almond milk (we have lactose issues)
- Chocolate almond milk case of individual portions (does not require refrig)
Lunch Food:
- Bread
- individual snack pack variety of some sort
- sliced cheese and one package of lunch meat ( alternative from peanut butter)
- case of V8 fusion
- case of water
- 1 bag of Tostitos and another bag of some other chip
Dinner Food:
- Stouffers Lasagna or Pizza for one night
- Salmon for another night
- Taco Kit for another night
- Hot Dogs and buns for another night
- Salad
- Frozen vegetable/bag of baby carrots
- Refried Beans
Note: that some of the above can easily be taken with us (i.e Hot Dogs,Taco Kit,canned goods, drinks) and consumed as snacks or lunch on the drive back home.
We also tend to get two bottles of already mixed beverages from the BJ's Liquor store. These usually do not travel home with us unless they have not been opened.
Hope it helps.
Oh, we usually take a small foldable cooler for the frozen items on the way down, but consume all items needing refrigeration during our stay. From BJ's to the resort it is a little overcrowded, but at least it is only for 15 minutes and not 10 hours.
If you do have a car and need to go to a local grocery store I highly recommend the Food Lion that is over by SSR, it is a little north of the Goodings intersection but well worth the trip. I would not go to Goodings, not a great selection and overpriced IMO.

Cook away