You can do that too. Signage in the airport leading you to the local buses may not be very helpful so when you arrive you may want to ask someone who looks like they should know. Also, make sure you take the 62 in the right direction since both northbound and southbound 62 buses make the same loop through the terminals. No change is given on the 62, have exact change (or at least two singles). At Newark I think you would buy a Metrocard - put on enough money for both PATH trips and perhaps a few subway / NYC bus trips if you will be taking them.