If I were you, I'd play it safe and book a later flight back to EWR. Since you're not familiar with the area, it's better to give yourself some extra time in case there are any unexpected delays or problems. Another option you could consider is booking a flight for the next day if it works better with your fiancé's work schedule.I've always believed that, it's always a good idea to have a bit of extra time when planning flights. Rushing around can be super stressful and might cause all sorts of issues.
