The 4th of July is a sell out weekend for most if not all of the parks. I would like to say that if you are not a passholder or resort room key holder yet, it may be difficult. I have several security host friends and they can tell horror stories of people who try to go to the resorts to park just to watch the fireworks. With all the added security precautions and pressures they are having to remember and deal with, please remember what THEY are there to do.
If anyone suggests that you go to one of the resorts please "smile" and thank. This was always frowned upon well in recent years anyway. But in these uncertain times, trying to tell a little white lie to gain access is no longer a safe suggestion.
We may cause them to miss a real "bad character". That having been said, One year I could not get into the parks and just like people do on the interstate here in Florida, I simply pulled over on the side of the road outside EPCOT and had a lovely show.
Hope you get other great solutions.