We are going today and tom! yeah!
Never been July 4 but...been many other times.
Are you staying at a Hershey Resort, if so you can get in an hour earlier than most people just like EMH at Disney. It is so worth it, we had the place to ourselves last time although only two sections are open. Comet hollow and Founders Circle but at least we got the beg of the park done and over with.
If not go in and go right to the back or right to Stormrunner if you like the rollercoasters, this line can get outrageoues later, You can get Stormrunner and Sidewinder done before the crowds make it back that far. Then go back to the beg later in the day and even leave and go do Chocolate World and come back in.
Have fun, if you have any other questions, let me know. I can proably answer better after I have had my refresher course for the season!