Travel advice for my nola trip

Well - our experience with Newark (4 transfers and 2 stopovers) is that you have to be very carefull to allow enough time to get back to the airport, through security and to your assigned gate in time. Once we had a 3 hour layover, but due to the time of day and large amount of people we barely managed to get through security and to the correct gate within that time.

Is the 8 hour layover on the way to or from the US ? If it is on the way over you also have to go through Immigrations and customs, and that is going to take some time too. If it is on the way home you may have less time on your hand than you think. All of our three return flights were delayed at arrival in NY for at least an hour. On one occation we got stuck for 4 hours on the tarmack waiting for a gate to clear so we could enter the terminal.

Bottom line - you'll have maybe 4 hours - 5 max to get to NY and back. If you are willing to risk it, you could take the train to from Newark to Penn Station and walk to Empire State Building from there or catch the subway to another destination whichever you like. You wouldn't have a lot of time and would have to watch the clock, but it probably would be doable.

We have not done this during a layover but have taken the train to Penn Station a few years ago when we had a 2 day stopover in NY on the way home. As far as I remember we took the airport train to the Newark station and then another train to Penn Station. Took about 30 minutes one way all total.