i second the moleskin. Daughter and I both got blisters, even though we had been "training" with three miles a day walks to get ready. Moleskin was a lifesaver, very comfy. Dont forget small scissors to cut it with.
Also, take a pic. of your parking place. When you are too tired to remember you will be glad you have it. Plus it makes a cute pic for the scrapbook.
All my daughters said that they loved getting there early, we went 30 minutes before opening.
Also, if the parks are open late enough, go home and have a rest and then go back. I dont know if that is as important this time of the year, but it made our trip at Easter this past April.
I would recommend having a general plan for every park. For example, at DHS, Toy Story Mania is always crowded. Go there first or at least get FP before you do anything else. Find out which rides are the newest, most popular and try to do those first.
Have a great time!! Trying not to be too jealous of you!!