If you go the turnpike from grove city, you're into about an hour or more of city driving (Pittsburgh). The easiest route for you would be to go out I-80 to Bellefonte... Then hit I-99 south for about 10 miles then onto Route 322 east all the way to Hershey. Which campground are you staying at? We've stayed all three of the main ones in the area, and two of them multiple times... If you don't have reservations yet, I have a list of my favorite sites that might be helpful.
2015 Coachmen Apex 288BHS
2014 Toyota Tundra CrewMax 5.7L