Two suggestions. If you are coming east on I-80, drop down Rt. 33 in Pennsylvania to I-78 then into New Jersey. There is construction at the I-80/I-287 interchange in New Jersey and traffic there is a mess. Best to avoid it if you can.
Second, if it fits into your schedule plan to arrive Sunday morning. That is when traffic in New Jersey is the lightest. Stay overnight on Saturday in the Poconos and drive in the next day. Check with Liberty Harbor how early you can arrive. If Sunday doesn't work, Saturday is your next best timeframe. If that doesn't work don't get into New Jersey until 9 a.m. to avoid the morning rush hour.