Garden Grocer was great for us.
We took an airplane, and figured that the GG delivery fee was less than the cost of checking one bag of non-perishables. We did not have a rental car, so local groceries were not a good option.
The food was waiting for us in the cabin -- milk in the fridge & ice cream in the freezer. Everything in my order was correct. Even the fruit was ripe.
I ordered cereal (my kids equate vacations with those little boxes of sugary cereal), milk, water (tap water had a funny taste), sandwich stuff, one pasta dinner, and lots of snacks to carrying around the parks. I was afraid of ordering too much, but we ran out of a few things in the middle of the week, so I did have to stop at the Fort stores. Expensive, and hard to carry everything on the bus. Also, while I don't mind some light cooking on vacation, grocery shopping seems like a chore.
Have fun in the cabin. We had a wonderful time and can't wait to go back.
Me, DH, and four kids, ages 10,7,4,1.