Ken, always enjoy your pictures.I was right near there this Sunday about 5pm, near Lake Aeroflex. Found a mile marker I missed in the fall because of heavy brush. Unfortunately, I haven't figured out yet how to post pictures!
Did you realize you were right at Camp Nordland, a German/American Bund camp that was shut down by the government around the time of WW II? The L&HR delivered Germans via the Sussex Railroad from East Jersey,Newark, and NY City right near where you took the picture of the electrical relay box at Lake Iliff. The building is now part of Hillside Park.
Lifecare Mews is a retirement community being built by the same company who bought the L&HR and Lackawanna Cutoff back in the 1980's. It's back on schedule to be built after working out utility problems. I'm familiar with the owner, and I've got some pics of the ROW from inside. There was a mile marker back there but looks like it got cleared out years ago. The Mulford station was pretty much where you took the picture of the small structure near the LifeCare Mews sign. Haven't been able to track down a picture of that station yet. My records show abandonement in 1933. Thanks for your offer to help with the preservation of structures on the ROW. As soon as I hear anything I'll let you know.