Nice shots. When I first looked at them, I thought we must have been leapfrogging each other- and I didn't remember anyone else out chasing, that day.
Then I took a closer look at the date of your first trip. I was chasing on the last day before Conjob (March 31 1976) and you were out during CR's first month.
Looks like you had slightly better weather than I did...
As for the locations you weren't sure of:
The two switching shots are at the Chester Industrial Park, from Black Meadow Road. It no longer has rail service (and was the site of the last operating diamond in Orange County- I think it's still there, buried in the weeds.)
The two labeled 'Heading to Hudson Yard' look to be in reverse order, at the Covered Bridge Rd. crossing in New Milford.
Tell-Tale shot is from the (now gone) Wisner Road bridge, north of Warwick; train is heading from north from Warwick toward Greycourt and Maybrook.
Milepost shot is at Sugar Loaf, at the King's Highway crossing, northbound (location of the former East Chester station, moved there in the early seventies).
The unknown long shot is about a quarter mile north, taken from King's Highway. The train is southbound, returning to Warwick.