ok I have done this twice now, and all I can say is keep a smile on!
The parks get hugely busy very, very early. Infact the MK was full to capacity at 11:45 one time. If you want to see the fireworks with the Castle as a backdrop you will have to get a spot really early on as everyone is thinking the same thing as you and it is a fight. HOwever, Disney has thought of this and the fireworks are so much more spectactular on the 4th. They tend to do them 360 so no matter where you are, you have them surrounding you. I will say though that we were forced to watch them from Tomorrowland as they rope off the lands of the MK when it is close to the Fireworks celebrations commencing so wherever you are…you stay until it is over!
One year we left the park early and went over to the Poly for dinner and caught the fireworks from the Luau beach area which was fab but now lots of people have caught onto that also and so that can get rammed also.
I hope I have helped and not scared you! :laugh: