I carry the bag for the 4 of us - so backpack it is.
-ziploc bag for each phone
-sunscreen
-chapstick
-hand sanitizer (clipped to the outside of the bag)
-bandaids
-pain killer in adult and children's strengths
-allergy med (if anyone seems to need it...otherwise we leave it in the room)
- phone charge cord, extra backup charger
- kids' cameras
-ID, CC, small amount of cash, just in case
-pressed penny stuff
-poncho for me, rain jackets for the kids
-small snacks for the kids
-kids' autograph books and pens
-my mini notebook and a pencil - I keep a backup of ADR times and confirmation numbers, FP+, and everything we need for our trip, and I also jot down little things that the kids say, or things that they liked - it becomes my own little memory book when we return.
And this year I'm thinking I might bring a set of flip flops for me when it rains. I wore my sketchers last time and they did not do well when they got wet - and since it rained (a lot) everyday we were there, they never got a chance to dry out. I ended up with blisters for the first time, and I honestly think it was because my feet were so wet. (No one else had any issue...) So -flip flops and ziplock so I can swap out the footwear for the inevitable rain storm.
