Transiting through JFK from Dublin to Orlando in November and will have cleared US Immigration in Dublin before we travel.Travelling with Delta

I believe that we will arrive at T4 from Dublin and depart from T2 to Orlando, how do you get from T4 to T2 and how frequent are transfer options.

There is a continuous loop air-train that runs between the terminals. Trains run every few minutes.

http://www.panynj.gov/airports/jfk-airtrain.html

The connection is easy but could still take 45 minutes including security. The Airtrain is your best bet.

I would allow more time than that if you have checked luggage. You will have cleared Immigration and Customs - but if you have checked luggage that does not go all the way to Orlando it can take forever for it to arrive on the carousel.

If your luggage is checked through you should be OK - IF your plane is on time.

I am risk averse and never accept a connection less than 2 hours anywhere.

the air train is free within the airport. once you are in the arrivals area look for the air train signs. you will still have to go through security at Terminal 2.

We should pay attention to what the OP actually says and not interject unnecessary drama into this. The airline is Delta, which has flights in both Terminal 4 and Terminal 2. There should be no change of airlines, and bags should be checked all the way through, just as on any other domestic flight. The OP is already ticketed, so this isn't about arranging flights.

Just follow the Airtrain advice, and you'll be fine. I think Delta may still offer a bus shuttle over to Terminal 2 directly from Terminal 4, but I still prefer the Airtrain.