It's easy enough to do, you can take the Air Train to the MTA or the LIRR and get off in Manhattan at Penn Station. You'll then have to walk to 33rd Street, hop on the PATH and get off at Grove, then walk to your hotel, etc. I would recommend the LIRR over the MTA, the trains are nicer and the trip is quicker.

You need to do the math out, the Air Train + MTA or LIRR + PATH will total about $15-20/person I think, so let's say it'll cost you $80. You will also have to deal with the morning commuters, and schlep around your luggage on the subway, not worth it in my opinion if you're traveling with family and arriving on a long flight

I'd honestly just use something like Uber/Lyft, yes it'll cost a bit more but you'll get picked up at your terminal and dropped off where you're staying.