Well, it depends on your definition of close. Lyndhurst is down the hill, on Broadway. It's not that far but it's a good hike. There will be plenty of people going to and from the hotel, so if you need a ride that should not be a problem.
There is bus service up and down Broadway. Check with the hotel on what the schedule might be. Finally, there is Metro North service in Tarrytown if you want to take the train into NYC or elsewhere. The trains run quite frequently. Off peak fare into Manhattan is $9.00 one way. However, the train station is nowhere near Lyndhurst/Marriott. Check with the hotel about that also.