There is no "stop and identify" law or requirement in PA. We have been able to find no requirements that a person identify themselves, even where the requirements for RAS or Probable Cause are met.
Understandably, although you have your rights, you may end up complicating your encounter to your own disadvantage, so you may wish to use your best discretion!
Example: last summer I went to a open concert in a park in downtown York. I was open carrying a XD45 5" OWB. I noticed a uniformed city LEO making his way through the crowd, apparently socializing. I was taking photos of the event and turned my attention to the camera for a bit, then heard those words we all fear...
"Sir, can I ask you a question?" coming from behind me. It was the LEO. He wanted to talk to me about my...
...digital camera! The horrors!!
No lie, we chatted a good 20 minutes about digital cameras and digital photography. His daughter wanted one for Christmas, and he was looking for pointers. He did end up asking me about my open carry, but only after our friendly chat about photography. And he never asked for any ID, although he did ask if I had my License To Carry Firearms he never asked to see it. Pretty cool encounter in my opinion! This guy was a PRO!!
You will find the atmosphere in PA to be a mixed bag. We truly are "Philly in the east, Pitt in the west, and Arkansas in the middle.
On a side note, I love Virginia, It is one of my favorite states to visit. I hope you find your visit in PA as enjoyable.