If you're looking for something to do Friday or Saturday morning or early afternoon before Port Royal consider a visit to Latimore Valley Fair Grounds home of the Eastern Museum of Motor Racing. The Museum is opened Friday from 10 to 4 and on Saturday they have the Gettysburg Region, Antique Automobile Club of America at the fair grounds.
There will cars on display this year at Port Royal aswell. There is usally dozens of cars on display. And "hot laps" for them as well during intermission.
Been to the museum many times in the past. I also used to stop by Lynn Paxton's shop when I was down that way too. Never knew who would walk in while you were there.