stations that once exisited-

[lensovet]

The most problematic part of extending the PATH south is having to go under the Route 21 bridge while also passing over the Raritan Valley Line and the old LVRR. Everything else besides that is mostly smooth sailing, although some modifications may be needed for McCarter Highway south of the former South Street station site.

PATH already has some steep routing in and out of Newark Penn. I don't expect this will cause issues.
I am curious if they will make the LVRR flyover also be the location of the NEC flyover in order to use the land reserved for PATH between the NEC and the AirTrain. If not, they might have to take land from the container terminal to extend the walkway (probably not an issue). It doesn't make sesne to cross over before the LVRR overpass because of the freight sidings there.

this whole discussion (and it's my fault for continuing it) would probably be better served here: viewtopic.php?f=68&t=104586&start=285