Before you scoff and say, "It can't be done!", hear me out on this. You really can do all four of Walt Disney World's parks in one day and feel like you've gotten the maximum out of each one — if you know what you're doing. While I don't recommend this whirlwind day for anyone who has never visited Walt Disney World in the past, for anyone who has been there a time or two, this is the guide for you.
1. Plan, plan, plan
I can't stress enough how important it is to plan ahead. Take a look at all four of the parks' attractions and pick out the ones you want to do the most. Also take a look at the park hours and days. If you can be flexible with when you go, do! Consider going during times of the year when the parks are slower (October, February) and days that are less busy (weekdays). Write down your detailed plan as a checklist so you can be sure to stick with it the best you can.
2. Plan on a long day
Once you've looked at the park hours, start to map out your day, starting at park opening and going until park closing. Whichever park opens first is obviously where you should start, and you should end at the park with the latest closing. Also consider which park closes first, usually Animal Kingdom, and start there so you know you can fit that in. Keep in mind, though, that during off-peak times of year, the park hours might be slightly shorter due to lower attendance. It's OK, you can still see it all.
3. Put the park puzzle pieces together by time
If you have shows you want to see at each park, make note of the times of those. I never, ever miss The Festival of the Lion King at Animal Kingdom, so if you have a show like that, make sure to put it at the top of your priority list. (Your can't-miss show should also be The Festival of the Lion King because it is literally the best show in the entire Walt Disney World resort.) In jotting down these times, you might have to sacrifice some things because a lot of shows are only in the mornings and early afternoons. Rank them in order of what you absolutely cannot miss.
Another tip: be strategic with your FastPass and definitely don't count on it. Think about which ride lines are usually long and when you'll be there and keep in mind that you won't be at any one of the parks for a significant amount of time, so unless your FastPass time makes sense with the schedule you've given yourself, don't worry about it.
4. Put the park puzzle pieces in order by location
Now that you've picked out what you absolutely have to see and where you should be when, take a look at the park maps and plan out your time there. Take into account the fact that the parks close from the back to the front, so you should start there so you don't miss anything. Try to strategize where you'll go and when, but make sure to build in time to get from park to park and time to eat.
5. Think about how you'll get from park to park
I was living in Orlando, FL, when I used to do the four-park day, so I would drive to the resort. The few times I tried to take the Disney shuttle between parks ended up taking a very, very long time, so I found that driving was more efficient. However, I understand that not everyone has that option. Taking Disney transportation is fine, but just remember how much time that will take up.
6. Bring your food along
Listen, Disney food is great, but unless you're visiting the parks specifically to get a turkey leg or a Dole Whip, skip them this time and just pack some snacks in your purse that you can eat while on the move. I always used to pack two peanut butter sandwiches, some crackers, a couple apples, and maybe a protein bar. I also made sure to eat breakfast before arriving.
7. Skip anything unnecessary
Unless the lines are unbelievably short, skip anything that's not on your list. I have definitely run up to a Goofy waiting for pictures when only one other person was there, even if I hadn't planned on it, but if it's not a priority, I skip it. Also, don't bother with merchandise during the day. Chances are, you'll end your day at Magic Kingdom because it's almost always the last park open, and you can do all your shopping on Main Street USA, which stays open until all the guests have left the park. Even if the park closes at 10 p.m., those shops will stay open later if people are still shopping.