I ALWAYS ship a box of food,snacks, gifts,etc. One year I even shipped easter baskets since we were there over Easter(never again!) Such an incredible savings. I have never shipped liquid, that might be a little scary and heavy=expensive. It was very simple, Disney was very helpful.
To be honest, my DH owns and operates 2 grocery stores, so it is painful to buy things anywhere else. (not gonna happen) Hope this helps.
By the way, you are from the twin/multiples mama thread. Good to see you again. I am not very good about posting on a regular basis.
Your girls are beautiful. I didn't have the nerve to take my twins until they were 6 (they could tie their shoes!!!) Good luck and enjoy!