You're going to need to run the air conditioner at night and that means full hook up sites. You won't make any friends boondocking and running a genny all night. You're going to need to make reservations, and it may already be too late for July 4th.
As an alternative to a fixed set of things you want to see, you could use RV Parky and Allstays apps to find a place near where you want to stop and then check the reviews on RVParkReviews.com to see what the place is like safety and activities wise. Then call the park directly for a space. Last minute cancellations normally aren't reflected in online reservation programs.
Plan on 5 hours and 250 miles a day when traveling.