Our 2003 July 4th experience: We were staying at the BCV
We went to MGM till about 1 -- not crowded at all. Could not believe how empty it was. We rode RnR 3X in a row when we got there. Hung out at SAB in the afternoon, went to Narcossees for dinner, watched MK fireworks from Narcoossees, drove back to BC and walked down to the International Gateway and saw Illuminations and 4th fw from there. It was a perfect day.
Our reservations for Narcossees was for 6:40, the MK music was piped in and we had a perfect spot on the porch. We leisurely walked back to our car parked at GF and drove back to BC. Of course the crowds from MK have to get to the parking lot which takes several minutes, so our drive back was on empty roads.
On another note, one thing our family realized last summer was that we loved Disney even when it was hot and crowded (most of our trips have been off season). I think your plan and your attitude has a lot to do with how much fun you will have.