Which lines for a first time visitor?

Of all the east coast transit systems, NJT has been the one I have spent the least time. I would like to make a trip in the spring to rectify that.

I have ridden only the Gladstone line, the Princeton Dinky -- along with the NEC -- and the AC line. Primary objective for this trip will be to take photos and I will be driving this trip as opposed to riding on my previous few visits. Of all the motive power I am most interested in the PL42s (or whatever the model is). Is there any of the lines that these units more frequently more than others? Or any lines they never run on? Is motive power assignments fairly random or is there any patterns such as: you only see them at rush hour, or only off peak, never on weekends, etc???

I am probably least interested in the dual modes, as I have seen some of those already. So please comment on lines heavy or exclusively using that model.

What lines would have the greatest variety of motive power? and which lines would have the least?

Also about 6 months ago I did see some Metro North F40s running out of Hoboken. Are those still running? And are they only used on the Port Jervis Line? Same as the other question above, do you tend to see them only at rush hour, etc, etc.

So where would be best for a first timer to go?

For PL42s and F40s, go for the Port Jervis Line or the Main or Bergen County Lines. I think PL42s run on them, for the F40s, they generally on the expresses that go all the way to Port Jervis. The PL42s also run on the diesels up to Hakettstown on the Montclair Boonton Line and the Morris and Essex Line. I think they pretty much moved all the PL42s off the North Jersey Coast Line once they started the one-seat service to New York and the service to Hoboken from Long Branch, so you should avoid there as it's pretty much all ALP-45 and -46.

For greatest desiel variety, visit the Port Jervis, Main, and Bergen County Lines. For greatest electric variety, the NEC might be the best. And for a nice mix of both try the Morris and Essex Line between Newark and Summit on weekdays.

If you want the best variety, I recommend as Nicholas posted, the Main/Bergen County Lines.. perhaps west of Ridgewood, as Ridgewood has cruddy contrast lighting that will kill your photos of Westbounds, also the Morristown line has a good share, perhaps go to Denville for that, so you can get both the Boonton and Morristown lines in one spot, maximum diesel. Avoid the Morristown line on weekends, you will need a weekday for that.