I was there a couple of years ago at that time of year and they did the 4th of July fireworks on the 3rd and the 4th at the Magic Kingdom. So we decided to do the 4th on the 3rd, so if they still do this it might be a good option for you. Then maybe do Epcot on the 4th. It will be hot and crowded, but it always is in the summer. So go with a lot of patience, and plan to take breaks back at your resort pool to cool off. Don't plan to do everything, since lines are longer. I just got back from the world a couple of weeks ago and I was so surprised at all we could do in one day in february that would take us 2-3 days in late June. Have fun!