I don't do the antiperspirant on my feet. Instead I wear liner socks (thin, nylon/lycra socks. Brandname is usually something like Coolmax.) under my regularly (hiking) socks. But, then, I also do Disney at Thanksgiving time (or at least my last three or four trips have been that time of year) and I wear hiking boots (comfort, stability, keep my feet warm on cool evenings).
I always bring a backpack into the parks with me. But, then, I'm seldom without a backpack in daily life, so it's not a big deal for me. Having a pack allows me to bring and/or remove layers of clothing as needed (again, see note about doing Disney at Thanksgiving). I do try to double up (my light jacket is a waterproof/breathable shell that, along with a light weight fleece and some waterproof/breathable pants get me through just about anything the weather can throw at me). The biggest problem for me is convincing my family that my pack is not their pack (I'm single and do Disney with my family, my sister, BIL and their two young kids). The general rule is "you put something in that's bigger or heavier than a park map, you help carry it". And, most of the time, that works. I do carry a fairly small pack, so that limits the amount and weight of stuff I can carry.
I do bring food into the parks, generally snacks and sometimes lunch. But, here's the thing, it's stuff that I want to eat. I don't generally eat a lot of junk food or even a lot of prepackaged/processed food at home. So, having poptarts and wheat thins, beef jerkey and especially M&Ms and Hersey's miniatures are almost as good as Mickey Bars and Dole whips (and will at least get me through morning snack and somethign sweet after meals). I don't know how well that would work with younger kids, but it's something to think about.
I also prefer apples to french fries with my meals. So, if we're doing counter service, I'll often get just a burger or something and then supplement it with an apple and something sweet from my pack. Saves money and generally I'm happier.
I carry a Brita bottle with a filter. The wide mouth makes it easy to fill up at a water fountain or rest room and the filter helps with the taste. But, again, I also use a Brita filter on my water bottle I use at work, so I'm used to the taste. For meals, sometimes I carry some powdered drink mix to be added to a glass of ice water.
Generally, I prefer not to take a break back at the room during the day. My sister's kids are good about napping in the stroller. Plus, they don't get up as early as the 'rents and me. M&D and I are usually at the park when it opens and get fastpasses and do the cool rides we (okay, it's usually me, except Jungle Cruise, that one is one of Mom's favorites) want to before the crowds get big. By that time, it's time for morning snack while waiting for the rest of the family to arrive. For a break during the day I'm usually good with a nice, calm ride or show that I can nap through in the midafternoon. Universe of Energy, Hall of Presidents, waiting for Festival of the Lion King, all great times for naps. My parents are also prone to napping during shows. Mom is convinced she's never seen all of Hall of Presidents in one sitting. But, I can also sleep just about anywhere and generally only need a 20-30 minute "powernap" to be recharged and ready to go again. To me, it makes more sense to do that than to spend the hour+ that it can take for round trip transportation to the room.
I can see not pre-buying non-Disney souveniers. What my sister does (and her kids are 2 and 5 at this point) is bring the souveniers from previous trips. Yes, it's the same light-up Buzz Lightyear that they bought three years ago and that the kids play with at home regularly. But, with a little cleaning and a fresh set of batteries, her kids are just as excited about it as if they had gotten something new.
I always bring something with me to do during lines/long waits for shows or parades. For lines, I like a yo-yo. For longer waits, I have a book or something else to read (often on my palm pilot). A little matchbox car or two or maybe a plastic dino lets me amuse myself (yes, I'm 30. What's your point?) and means I can help entertain my nephews as well. Someone also mentioned little things of bubbles. I hadn't thought about that, but have a few wedding bubble containers around and I might bring some with my this time.
, driving back and forth everynight. I'm glad to hear about the night EMH at AK it's our second favorite park and it seems we can never get enough time there. I second the vote for WDW transportation. I love being driven around. When on vacation, I like to park the car and leave it parked, or should I say DH likes to leave it parked.
It's not 
With the 5 of us, and sneakers & sandals for all, it actually helped a lot.
