One park per day. We really love AK and because of the show schedules and usual early closing I can't imagine trying to do them together.
Oh good, that's what I thought. But I could tell some others were advising on doing those parks together on one day, so I wasn't sure.
I like the AK plan someone outlined above. You could then decide if it's too hot and you want to leave, or spend some leisurely time on the trails, grab lunch at Flame Tree, use the app to check wait times and re-ride any favorites.
At DHS, do you have any Star Wars fans? My 7 year old son and 9 year old daughter really loved Jedi Training Academy, which is a free participation show, but you have to show up early to sign up for a time. Although it's open to kids through 12, on our day, my 9.5 year old was one of the oldest. I think an older child would only like it if they were very comfortable kind of being a ham on stage and really love star wars.
If interested in that, I'd show up at rope drop (be at the gates by 30-45 min prior to scheduled opening) head straight to Jedi Training sign-ups (the participating kids must go to sign up with you)
After registered, head to Rockin Roller Coaster standby
Have FP+ scheduled later for Toy Story and Tower of Terror and your choice of other (we used it on Star Tours, whose standby times vary a lot throughout the day. can often be found quite short, though)
After RnR, ride again if lines haven't built yet. if Tower lines are short, ride it standby.
Pick shows to watch working around meals, Jedi Training or FP times you already have (toy story is hard to move once you get it).
If you don't want Jedi Training, my plan would be similar, but skip the sign up and either head straight to Toy Story for a standby ride, ro straight to RnR for multiple rides.
I like to schedule FP+ starting 10:30-11:00 but I don't have a goal of obtaining extras, so completing them early isn't a focus for me. My primary concern is using them when they are really necessary, saving me the most time, not using one when the standby lines weren't bad to begin with.