The afternoon break hasnt really worked for us, but it works for a great number of people. Its something different with each child. My son didnt nap. He would usually fall asleep on the bus and wake up as soon as we got off the bus. Only twice did he stay asleep, and one of those times we were coming in for the day. It was 5pm on our 5th day after me unsuccessfully trying to get him to nap in the room and in the stroller on all of the other days. He was talking about his day and then asked to sit on my lap. He woke up the next morning 14 hours later.
With my daughter you have to get all your touring in for the day at once. She can stay in a park 8 hours as long as she is kept as cool as possible and hydrated and gets periodic breaks, but once she gets back to the resort that is it. Ive been able to get her back to the park if we just came back to get cleaned up and she had a BBB appointment in the afternoon, but as far as going back just to do the park in the evening, it was a no go. I ended up missing Wishes and MSEP last trip because I waited until the last day and we took an afternoon break. She was apologetic later, but even though my reasoning for doing so was sound I really should have known better than to leave something that important to me until the end of the trip.
Im hoping this changes at some point as I found out on our first trip in November 2010, I so enjoy the parks after dark. Weve gone in June since then and of course it gets dark much later. But my main goal is to keep everyone from getting over stimulated and over tired. I go at their pace and follow their cues, especially those of my daughter who is light years past stroller age and has to walk everywhere.
I do bring a first aid kit with me; but if something happens Id rather find a spot to sit and deal with it than to try to find a first aid place. But then Im used to packing mine because we go on various outings (zoo, touring farms, parks, museums with outdoor areas, nature walks).
Along with a change of clothes, I have learned to toss a towel into the bottom of the stroller for the water play areas. My stroller will still fold up completely with the towel and a change of clothes in the bottom. My daughter can get dry in the sun, but my son gets soaked to the bone in that Epcot splash pad. A towel is also good for blocking out the sun if someone needs some quiet time in the stroller.
Packing has been an exercise where I learn a bit each trip I take. I love to travel so I started each child traveling pretty early in life. By the time my daughter was 3 or so, I learned not to over pack. Then I got pregnant with her brother when she was six. I still shake my head at the picture of all of our stuff by the door before my sons first vacation. But again over time I learned. Comparing my packing lists over time and my garden grocer orders from our first Disney trip to this one show it.
Both of your children are still in the Garanimals stage. I love that line of clothing from Wal-Mart and it is great for travel. The pieces are inexpensive and comfortable and (as I found out on our first trip when my then 10 month old son had a massive blow-out in MK), because they are so inexpensive, it doesnt hurt if theres a piece you just cant save.
I have done laundry on our trips and I just use a laundry bag from the hotel.
My daughter and I have personal fans around our necks and we travel with 1 or 2 misting fans; but, having a fan to clip to my sons stroller was great. He also now has Peltor ear muffs so we can watch the fireworks. He loves to watch them, but the noise made him a bit uncomfortable. I got them for sporting events we go to and he has been so much more comfortable Ill be packing them for Disney. I bring 2 different size zip lock bags. I have gallon size for various things like electronics autograph books and extra clothes. And I have smaller ones for snacks we bring from the room. My son also uses those snack trap cups. They are the ones with the lids that have splits in them so the children can reach in for the snack, but it wont spill. Great for finger snacks.
All in all I just remember that even though it would be inconvenient and even costly, pretty much anything except prescription meds can be replaced easily during the trip. I have lists and usually there are categories. One category is Must not leave these things behind and thats generally my sons ear muffs and any prescription medications we might have, which currently is just my sons breathing meds. He has reactive airway disease and has a nebulizer, inhalers, spacer and mask and the breathing solutions. I find that as long as I have everything in that must not leave this behind category, were okay.