We went last year with sister and her family. There was a total of 9 of us. It was easier and a better value for our two families to rent two cars. We arrived around 1100. Rented cars from Alamo (I think) since you could return the car directly to the Aulani. We headed to the visit the North Shore to grab lunch and soak it in. Headed back to Aulani to check in. After we checked in and got our stuff unloaded, we checked out the kitchen, and made a list of things we needed. W kinda planned a menu for the week during the plane ride. We left the dads with the kids and then headed back out to shop for the week. First we went to Target to get some laundry detergent for the week and some other things like foil, baggies, suntan lotion and misc items. Then we headed to Costco. They are both close to each other and easy drive. Our costco list was breakfast stuff( eggs, bread, cereal), some frozen stuff, sandwich cold cuts/cheese and we got some meat to BBQ one night. we also picked up ice cream and snacks. Before we left, we picked up two roasted chickens and ready made salads for our dinner that night, basically, we got managed to get enough food for the week. We had planned our outside dining adventures towards the end of our stay, after we had gone through our Costco food purchase and probably would be done with cooking. You can borrow BBQ utensils from the Aulani "rec room"(forget what it is called but you can get all your info there). There is also a rice cooker in every villa.
One of the things I forget to mention is that fare our mega food shopping trip, when we pulled in, the Aulani staff unloaded all of our groceries into plastic tubs and carted them all to our room for us. That was a nice touch. They are used to people coming in with groceries. There is also a small market across the street where you can pick up some odds and ends if you run out of something or miss something. It was reasonable enough. Just remember, you are in Hawaii some everything is gonna cost more. we figured out that we spent about $500 on food, snacks, and water during our costco run. That was enough to feed our group of 9 (4 adults, 5 kids). It was a huge savings. A little menu planning and buying the right food for the week really helped to make for a great vacation without breaking the bank on food options.