With JFK it will all depend on the weather/winds that particular day and (sometimes it seems) what mood the Controllers woke up in that morning . I myself have experienced days where they should have been on the 31s but stayed on the 4s all day. Other days have been split between 13L and 22L approaches.
I have not been spotting at LGA yet to offer up any info on that.
1. Which runways are likely to be in use at both JFK and LGA (is one runway direction favoured)?
2. Do the runways swap (such as LHR going from left to right each day on 27 approaches)?
To give you an idea, when I made a trip down to JFK this past Sunday, whoever was in charge of assigning runways must have woke up in a sh***y mood. Upon arriving at JFK at sunrise they were landing the 31s which lasted until roughly 7:30 and then they switched to the 22s with optional KK departures. That lasted only until about 9:30 and then they switched to the 13s until 11:45 when they made the switch to 22L/13L split for arrivals and 22R/13R departures. This caused us to miss quite a few good arrivals that went to 13L instead of 22L. Then finally at 5:05p they went all arrivals on 22L.
No problem - Yes it is possible to snap some shots from inside the terminals at BOS and DTW. If you look at a few of the threads, you will get an idea of the shots that can be taken from those locations. What days are you planning on being at JFK?
East of the Delaware, West of the Hudson, on the banks of the Old Raritan
Assuming you're going through the main terminal in DTW, everything is readable, and if you're a quick enough writer, you can knock off an entire face of the terminal from the train thing in 5 minutes. If your goal is photos, there are little dots on the window to cut down on insolation, and they'll ruin almost any photo you try for.