I love Penitentiary Glen! It's a great place for kids and adults alike. The wildlife rehabilitation area gives you an up-close look at various woodland creatures as they are nursed back to health--I was able to see a variety of birds during my visit, including a "teenage" bald eagle! The displays inside the wildlife center are interesting, and I got a kick out of trying to spot the queen in their bee colony. I also recommend birdwatching from one of the indoor rocking chairs; it's an excellent way to rest up after a long day of hiking!
Speaking of hiking, the park hosts a plethora of trails, which are well-maintained and lovely. The trails aren't particularly difficult to traverse (though some can be lengthy), perfect for a leisurely stroll or the occasional runner.
And if you have little ones, definitely make a point to visit when the mini railroad is in operation. Riding a tiny locomotive through the park remains a cherished childhood memory of mine, and it's something that I think most kids would get a kick out of. I believe the park also hosts a variety of other events as well, from art shows to stargazing parties. Truly, there's something for everyone at Penitentiary Glen!