I depends on when the 4th falls. If it leads into a weekend, then you have weekends crowds. Even with the holiday crowds with FOTL we never waited very long at all. The only time we had any wait more than 15 minutes, was if there had been a malfunction on a ride. The parks didn't seem much more crowded than the normal summer crowds (which are BIG). It was just the HUGE crowd at City Walk on July 4th. We watched the fireworks one year from IOA and the next from US. It was just about impossible to walk through City Walk after the display. If you view the fireworks from one of the parks, just don't be in a hurry to leave. Let the crowds at City Walk thin out.