Be prepared for major CROWDS. I am not talking busy day, I am talking butt to butt crowds.
Magic Kingdom will most likely be the first to close the turnstiles due to the crowds, and in the past it has happened around 10 am. This means that if you are there, stay, but if not, plan on going somewhere else.
Last year AK and MGM closed at around 12 but MGM opened back up around 5 because some of the crowds left. Ak has no fireworks and closes at 6 so being there is not an issue later in the day. Epcot did not close last year but did the two years previous.
If you are planning on doing some rides and attractions you will have hour to two hour waits for the popular ones.
I love the fireworks at Epcot but most people prefer to be at MK for their fireworks.
You will see more people sleeping in the grass on the 4th than you will ever see in an entire week at WDW. People get into the parks as early as they can and take naps on grass rather than going back to their resort and not getting back into the parks.
I have taken more pictures o the 4th and New Years Eve than I ever took in all my years visiting WDW, but I have no photos to show for it. I spend the day walking around soaking up the "happy" and volunteering to take photos for all the family groups that usually only have mom and the kids.
I will be there again this 4th and can't wait to spend the day in Epcot, enjoying the crowds and my margaritas.
By the way, if you want a good spot for the fireworks, plan on choosing the spot and staying there for hours. I usually settle down in my favorite place at around 6 pm for the 9 pm fireworks. Bring a good book and some toys for the kids, or you grab a spot while someone else take the kids for a few rides or for a walk to pick up dinner at a snack shop. Peggie