IsStatenIsland
PATH and the IND 6th Avenue Line are both centered on the same line, with the 2 PATH tracks being under the center of the street like a typical subway. The 2 local IND tracks are built around the PATH tracks and the express IND tracks are under all of that. The "PATH next to 6th Avenue Line" idea is a fiction of the MTA's subway maps intended for simplicity.

At least that's the general idea of this section, however there are complexities like access to PATH stations underneath the IND line, access to both PATH and an express stop, crossing subway lines like the L...

It's really hard to map this section of PATH correctly. There will definitely need to be physical visits to it just to piece it all together.