Please forgive me for being long-winded on this post, but hopefully you'll find it interesting.
Salisbury Mills station is a great place to railfan. The view eastbound from the platform looks downgrade across the Moodna Viaduct. You can also work in an automatic block signal in that angle. Looking westbound you can shoot eastbound commuters slowing for the station. In regard to train activity, and this is based on my 2002 employee timetable when I worked on the on the NJT Mainline/Bergen County/PVL/Port Jervis dispatch desk, NJT/MN obviously runs the most trains. The morning rush is all eastbound commuters from Port Jervis, Trains 48-58 (even-numbered). The first westbound is 51, departing Hoboken around 9am. The next scheduled eastbound is Train 60, departing Port Jervis around 1230pm. The afternoon rush started with the departure of Train 53 from Hoboken.
Freight-wise, the only train that ran on a daily basis west of Suffern while I was there was HO-8 (eastbound) and HO-9 (westbound), which ran out of Campbell Hall. They normally came out of Hall mid-morning and went west to either Port Jervis or 4 Story Jct. After they finished working Port or 4 Story Jct they would then proceed east, either back to Campbell Hall or on to Napera Chemical at Harriman. On most days that they went to Napera they would be ready to head west about the same time that Train 53 was approaching Harriman. We would usually hold the freight until 53 passed. HO-8/HO-9 were (still are?) rather small trains. A locomotive on each end and usually no more than 8-10 cars.
NYS&W would run SU-100 east from Port Jervis to Hudson Jct 3 to 4 times a week while westbound SU-99 usually ran on the days opposite of SU-100. SU-100/SU-99 usually showed up late on the 2nd trick or on the overnight 3rd trick. NS would run 42A west from Croxton to Port Jervis and points west, doing local switching all along the way. 43A would be the eastbound train, both always ran on the 3rd trick due to the amount of switching they did, often times leaving their train on the main while they did their work. Neither 42A or 43A had a regular schedule to them, although they usually ran 3-4 days a week. Note how NS reversed the time-honored tradition of numbering eastbound trains with even numbers and westbounds with odd numbers. Only the NS. For the rail history buffs, 42A/43A were the former OIBU/BUOI.
Anywhere along the Southern Tier between Port Jervis and Suffern is good for railfanning. Granted, the majority of trains are NJT/MN commuters but a train is a train is a train. If your primary interest is in freight ops, stay east of Suffern. H55/H56 comes out of Suffern mid-mornings and works the Bergen County, Mainline, and Paterson Yard 5-6 days a week. H80/H81 works the PVL 5-6 days a week and also goes to Croxton to swap the cars they switch off the PVL. Keep in mind that this information is from 2 years ago so I can't say for sure how accurate it still is.
Again, sorry for being so long-winded, I do hope you found it interesting, and of course if anyone can update me, please do so, I'd appreciate it.
Joe P :D