Knowing when parks close should be the 2nd priority to your park hopping day at Disney World.
You have decided that you and your family are going to go all-in and hit two or more parks in one day! While the task may seem daunting, don't let it get it you and start with planning ahead.
The hardest park to jump to is Animal Kingdom and I don't recommend making that hop unless you simply want to say you walked through it. Five hours is plenty of time to take in any Disney World park but A.K. will shorten your day.
On average days, the parks will close between 9 and 10 pm barring a late extended hour event and even then, fireworks shows will keep you in the parks long after. The closing times are typically meant to tell you when rides begin to stop letting you in line and when restaurants will close.
Animal Kingdom on the other hand closes at 7 pm or 8 pm and rarely stay open later. There are no after-hour fireworks at A.K. due to the animals in the park.
If you want to plan a long day at A.K. you need to hit this park first so you can ride the attractions and take in some of the really solid shows like The Lion King. If you dart over after 2:00 you won't do the entire list of what the park offers...but you will get back to your hotel room a lot earlier.
The only way to get to A.K., however, is to bus or drive. That is something to keep in mind when planning your jump. I always start my Animal Kingdom days at AK and then leave to hit another park later.