I have a couple of suggestions;
I would mail to the resort, make sure to put your info on the outside of the box, ressie #, and arrival date, and such. Some friends of ours always go this route and are happy. I don't think they have ever had a problem. I think that they have shipped, diaper and wipes, baby food, breakfast items, snacks and such.
Not sure now you are getting to resort, but you might want to think about a car service with one stop, to grab what you need. If you stop at a Publix, you can look up the store you would be stopping at, and print a list by aisle and look at the sales ad and bring coupons along for added savings. I would divide up the list and you take one part and DH take the other. We drive but always make a stop at publix before heading to the resort.
Just a quick thought on other ways we save money. Even with DDXDP, we like to use our credits wisely. .. So...We pick up bottled water, adult beverages, soft drinks, juice, ham and cheese from the deli, fruit, crackers or chips, grab some cookies to. We save a ton of money with the water, for the 2 of us we get a 24 pack last 7 night for about $4.00 ish, we take one out in the morning, and refill at counter service's, and throw away the bottle and take a fresh one out for the evening. As far as the ham and cheese and fruit we take that to the pool, we learned that our kids would eat this type of finger food before racing off to the pool again. So now that they are grown and starting families of their own we still enjoy this, also adult beverages or really any beverage at pool side are very costly. Just make sure to put the adult beverages in a plastic container for pool side. If you have a foldable cooler or insulated bag this works great for the pool and even the parks.
I hope this helps, Have a magical time