Maybe you should just plan on stopping at a Subway for a drink before you go? A local here probably would be more than happy to mail you a coupon if that wasn't a possibility.
Local Costcos have discount tickets, if you have a Costco card, you can enter any Costco nationwide. I'm assuming you don't have a AAA card. If you did, you don't have to be a local CA resident to get the discount... you just show your card and save the money. They don't ask for residency proof.