Question for the savvy NYC commuters. I know how to get between JFK-LGA. How do you go about getting from LGA-EWR and vice versa and between JFK-EWR and vice versa. I know heavy train use is involved, some more detail will be helpful.

Also I know the short call out is approx. 2 hours. I could stay about an hour east of JFK and 1:15 from LGA. Is that acceptable or do I need to be able to get to EWR within the 2 hours as well.