For the Farmingdale Price Parkway trackage, here's a google map that I added some notes to. There was a thread either here or another forum a few years ago. I used info that was posted then with what I saw & photographed. The 1978 LIRR Freight Maps have a good drawing of this along with the customers that were served. I don't have a copy of those maps but if someone else does maybe they can post this one.

Here's the text I have for the notes on the photo. Some of the info might have changed since then.
Farmingdale Price Parkway Rail Complex
Using Google Satellite image (Google Imagery, DigitalGlobe New York GIS ©2007) from 10/1/07.
This shows the area from several years ago. Notable is that Levitz Furniture is still there, since replaced by Lowes Home Center, and the PC Richard & Sons north warehouse still has track behind it (which has since been removed or paved over.
From the annotated image, these notes are indicated by the numbers and represent what exists now:
1 spur to warehouse taken out
between 1 and 2 track taken out or paved over
2 track exists
between 2 and 3 track taken out
3 small section of track in grass in parking lot
between 3 and 4 track exists
4 switch taken out
between 4 and 5 track taken out or paved over
5 switch to 2 tracks: one small section crosses road (Avon Court) and ends at low concrete wall along roadside; track is paved over in road; second track curves to west along roadside
between 5 and 6 track visible in grass and pavement
6 switch to 2 tracks
between 6 and 7 track runs along roadside and is paved over or buried in dirt
7 track crosses roadway, paved over but with rail visible
between 7 and 8 removed or paved over through parking lot
9 switch in weeds to 2 tracks between road and warehouse, both tracks in good condition
between 4 and 10 track taken out
10 2 tracks and switch partially visible in grass in Lowes parking lot
between 10 and 11 track exists
12 switch from mainline and second switch to 2 tracks of the complex
between 12 and 1 the section of track along Price Parkway to note 1 has been removed or paved over, with only a small section visible
13 spur taken out
NOTE: - much of the track that is visible is in weeds
- from the switch at note 5, the track had continued north to Daniel Street to service 2 or 3 warehouses as indicated in 1966 Freight Maps
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FYI #9 above was a Sears warehouse and #8 was a JC Penney building. I've also seen it mentioned somewhere that the track once ran further north to the State College. I haven't found the source for that again, so I don't know if that was really the case.