I've been lurking around here for a while, so I decided I should finally contribute. Long story short, I ended up making the trek to the tourist trap of Breezewood in search of the abandoned stretch of PA Turnpike (unfortunately I was by myself so I decided against probing too deep into the tunnel). What followed was a lot of inadvertent four wheeling (not on the turnpike due to the obnoxious jersey barrier roadblock), an ungodly expensive flashlight, and a pretty pleasant hike.
Some of my better pictures from the trip:
The abandoned cove valley service plaza (apparently [per the sign at the entrance] DCNR uses the employee access road to get on to the turnpike for patrols to stop vandalism, however there weren't tire tracks or footprints and I saw not a single soul)
Dali on a jersey barrier
I love you too, abandoned service plaza
They even welded the manholes shut (you can't make it out easily in this one, but there's four sloppy tack welds around the lid)
The Sideling Hill sign is gone (at least on the Eastern portal)
Southern Alleghenies Conservancy has welded the outer doors shut
A+ Security (the welded door is around the corner). The sign here warns of video cameras recording around to make sure you don't go into the upper area, but I have no idea where they would get power or record to.
I try to be artsy with my service equipment alcoves
The point where I realized I got ripped off on that flashlight from the rest stop (I think that blotch in the distance is light from the other end, but the inside of the tunnel itself is impressively dark)
No thanks, robot. I'd rather not, actually.
Looking back out (shortly afterwards I ate it face first into the snow trying to climb that retaining wall so I could poke around some more)
I receive good life advice from a tunnel wall
There's a grabiron ladder in here, I'm fairly certain it leads to the upper area
The lower floor of the side office area, the only place that awful flashlight works
graffiti artists are vulgar people
The road leading back
That's the highlights from my trip, I'm hoping to head back with extra flashlights and people to call the outside world if I trip and hurt my clumsy self.