I've done a Google search and there is no record of the shows performed there or at Valley Forge Music Fair online. It used to be such a treat and a special occasion to put on a tie and a sport coat, be driven by my parents to Fairmount Park and see a play starring someone we watched on TV. I met Anne Meara years later and told how much I enjoyed seeing her and her husband Jerry Stiller in two Neil Simon comedies, The Last of the Red Hot Lovers and The Prisoner of Second Avenue, at the Playhouse. After the curtain call they did a few minutes of their stand-up comedy act and joked about the difficulties of caring for children when touring in stock (the kid they were joking about grew up to become Ben Stiller.) Meara thanked me but said she hated doing stock because the conditions were so tough and you were always on the move. You only played one week in each theater and then went to the next one with very little rehearsal. In addition, when they were in Philadelphia, they usually cohosted the Mike Douglas Show (which was filmed in Philly) for the whole week.
It was also fun to see Peggy Cass live since we used to watch her every day on the syndicated To Tell the Truth panel show. She won a Tony Award and was nominated for an Oscar for her comic turn as Agnes Gooch in Auntie Mame, but she was best known as a TV personality in the age when celebrities would sit on panels and play guessing games with ordinary people. I don't know why but To Tell the Truth fascinated me. Three people would each claim to be a person with a quirky story or talent and the panel would have to guess who was the real one and which were the impostors. I actually kept a journal of the contestants, faithfully recording their stories and who was the real one. Cass, Bill Cullen, and Kitty Carlisle were the regular panelists and Garry Moore was the host. This was a 1970s version of the show which had earlier been on network TV during the 1950s and 60s which Bud Collyer, the radio and cartoon voice of Superman as the moderator. When the network cancelled panel shows like Truth, I've Got a Secret and What's My Line, syndication took over and the show ran in the late afternoon and early evening five days a week.