I have a spread sheet template I've used for years. I used to just print it, but now I also email it to myself. Mostly I now just use the email I send to myself. with the Disney app as back up.
I make a fuller spread sheet with park hours for all parks, emh, ADR's, confirmation #'s, etc. I also made a smaller cheat sheet version with just ADR's (and now FP+ tiems), and minimal info for the park we planned to visit each day. (MK, 9am-10pm, EMH to 1am, "Crytal Pal @7:15pm). I also use color coding: AM EMH is red, PM EM is BLUE, Fantasmic! time is green (Just F! @9pm), Wishes time is pink Mine looks a bit like LSUfan444's, but mine is a bit more condensed. Like for hours I have 9am-9pm, to11pm I know the blue =pm emh. then I have a block for 'plan" which says like MK or MK/HS for split days. ThenI have one block for listing FP+ and ADR. There too I abbreviate: P Pan, Splash. With a first tie group, you probably should spell it out a little more than I do, but color coding really helps my extended family.
Mostly, my family used the smaller cheat sheet as back up to keep track of ADR times (I'd now add FP plus to that list), so that's all we carry. The bigger one, we use in the hotel room. Each adult is responsible for reviewing it each am to memorize which park that day, and where/when of our dinner ADR. Mostly now I just use the email, with the paper as backup in my wallet. Other confirmation numbers I've rarely needed once we arrive. OH the BIG exception there is that you NEED your airline confirmation to get your return flight boarding passes!!!!! Remember too - if you keep the check luggage stickers on your bags- and your return conf #'s are the same, the number is on that tag. Otherwise we learned the hard way, it can be time consuming to look up your confirmation #'s on some airlines. Also keep a copy of your park ticket numbers (If not linked to WDW electronically) and you are using plastic cards.
Oh, I also find my phone amazingly useful for keeping track of all sorts of other details! Take a photo of all your ticket numbers. Also where you parked, what each child is wearing each morning (in case they get lost), and any other info sheets you might need. (In the event of a driving accident taking a photo of the person's ID is much faster than writing all their information.)
If you need maps, they are still available in glossy paper form all over WDW. You may want to make your own before you go, but they are easy to find if someone needs to replace.It would also be wise to sorta memorize the layout a bit before you go. Not 100%, but more the shape of each park. HS is especially confusing, but the rest are pretty easy.
I don't need the Disney app, and it can be slow, but that's another way to quickly navigate.
Driving around WDW, even as experienced as I am- we still use our in phone GPS.
I don't find the battery life to be too much of a problem. Make sure you have plenty of memory on your phone.
If your battery is not lasting long enough, it might be time to replace it. Over the life of my last phone, I replaced the battery three times! It made a huge difference! A new battery is $30 or less- and that's if you go through your carrier's store, less if you can find a discount phone battery store, or buy one online.
If you have teens, they will probably be rather savvy with the new Disney App, or keeping track of stuff electronically. While you should stay in charge, no doubt, one of your teens would be happy to help out by being the rapid response person.