Are you staying onsite? If so, you may want to take advantage of EMH mornings. One park per day will open one hour early to on-site guests only. EMH are as follows:
For MK -Sun and Thurs
For MGM- Tue and Sat
For AK- Mon and Fri
For Epcot- Wed
However, if you are not staying onsite, (or even if you are, but don't want to get to the park by 8:00) it's best to avoid these parks on their EMH days, as they tend to get very crowded later on. A good strategy in this case is to visit the park that had EMH the day before.
You may also want to take a look on Disney .com, for the schedule of events during your stay. Fireworks, for example, are only offered on certain days at the parks, so you may want to take that into consideration. Good luck, and have a great trip!