I have been thinking about this option but noticed Garden Grocer had a minimum order of $40 and a delivery fee I wasn't sure if it made sense. I really only need milk. But I guess I could think about getting breakfast supplies and diaper supplies from them instead of bringing it with us. Thanks!
Yes, Southwest rocks!

I just wasn't sure if you have to have the cooler "prepared" in any way or if you could just walk up with an empty cooler and check it. Can it be a hard- or soft-sided cooler? Any advice from anyone who has checked a cooler before????
Honestly, without much splurging or waste you can hit that $40 and still save money. For us, we hate the soda fountain drinks at disney, the local water really makes it just taste "off" compared to what we have at home. We usually order a 12 pack or two of soft drinks (two 12 packs=same $ as one refillable mug), usually some drinks for the kids, some fresh fruit, a bag of pretzels and maybe some peanut butter crackers, a box or two of breakfast bars....just stuff that will let you have a craving snack or a quick bite to tide over until the next meal without spending $20 on snacks at the food court or using 8 snack redemptions on the meal plan. Knowing you have an ice cold drink and a gnosh waiting on you in the room often makes that long bus ride home much more bearable.
We first used grocery delivery about 4 years ago at the beach, where on arrival day we either had to pack a huge cooler and lug it all the way up to the condo OR fight the crowds at the grocery store on an island where everyone checks in on the same day.....or pay $20 and our order is in our condo waiting on us when we check in, perishables already in the fridge etc. Once we used it, there was never any turning back and now pretty much every vacation it is our first option, our "go to" choice.
Southwest does indeed rock, and the magical transfer stuff is wonderful. We have used it 3 times now. Each time we just pack a carry on with our sleeping stuff (PJs, meds, tooth brush/tooth paste) and when we get to the hotel just tell bell services to hold the luggage till morning (it usually arrives about 1.5 hours after you do, so they would be waking you up with room delivery when it arrives.) Our flight usually gets into Orlando at around 8 p.m. so we are in our hotel room by 10 p.m., immediately in bed and get a good night's sleep, up bright and early at 6:30 the next morning and a bell services person is right there at the door with all our luggage. This is one of the things Disney has changed in the past 6 years that is absolutely outstanding, compared to other changes that have you smacking your head. They have a home run with magical transfer.
I have frequent flyer miles from biz travel, usually enough for two free tickets at any given point in a year. We still choose to buy tix through Southwest instead. Here is a SW trick, they publish their fares at very predictable, precise intervals. For instance, for week before Xmas travel we knew they published on the second tuesday in July (last year.) We logged on just after midnight and got four of the super saver fares (limited availability on any given flight) so our tixs were less than $90 each one way. Within a week the super saver ones were sold out and the cost would be $129 each, each way. So when you know your travel dates, figure out the fare publication date and hit your airline reservations the moment they come out. We actually booked air 4 months prior to booking disney hotel. (unlike air, disney hotel often gets cheaper the closer you get to travel date, their specials and promotions are based upon advanced bookings at any given property and might come as little as 60 days prior to your travel date. You can ALWAYs rebook your exact same trip with new offers to get the better pricing.)
Just a final "not that you asked" point - make sure you have the Disney Visa card. our neighbors across the street literally traveled same dates same hotel december 2009 and we were over a thousand $ cheaper (we buy meal plans and tix etc so did they) than they were just from the PIN offer we received via email. That 2009 experience is a repeat of the 2008 experience where we booked a "general public" booking via the specials online at the disney website at the Contemporary in June for December travel, and then rebooked 2 times with a travel specialist as new PINs came in. We reduced our bill by a little over $1,200 AND upgraded from garden wing parking lot view to tower room bay view. We could not have done that through "general public" offers via the disney website, and I checked. Even if you don't upgrade the rooms, the money you save could go to cirque de solie tix, for instance.
Ok, long rambling post over.