Car service, uber or drive your car service to EWR.

While I've used public transit in the past, it only takes one small failure in that chain of this train to the next to the next to create a problem with meeting your flight.

I drive or arrange transport via car service or "drive your car" service to the airport. In my town, there are a few retired folks who will drive you down to the airport in your car and pick you up on the way back. My guy is a retired firefighter (retired like 30 years) and does a great job.