You do not need a car to get out of New York in the fall. You need Grand Central and about ninety minutes.
Metro-North's Hudson Line runs north out of Grand Central along the east bank of the river, and from roughly the second week of October it turns into one of the better train rides in the country. The tracks sit close enough to the water that you're looking at the Hudson and the far bank the whole way. Sit on the left side going north. That's the entire trick and people who don't know it spend eighty minutes staring at a rock cut.
From us on East 62nd Street, Grand Central is easy: the F or Q from Lexington Av/63 St gets you there in a few minutes, or it's a twenty-minute walk down Lexington if the morning is nice. Buy tickets in the TrainTime app before you get on, because on-board fares cost more.
Timing, honestly. Peak color in the Hudson Highlands usually lands somewhere between mid-October and the first week of November, and it moves a little every year depending on the summer. Don't build a whole trip around one weekend. Any Saturday from early October to mid-November will give you something. What matters more is the train you pick: take one that leaves Grand Central before 10am. The later trains fill with everyone who had the same idea, the villages get busy after noon, and you want to be on a northbound platform with a coffee while it's still quiet.
The MTA has run extra weekend service on this line in past autumns, adding trains between Grand Central and Poughkeepsie on Saturdays and Sundays across the leaf-peeping window, plus additional Beacon trains on peak weekends. Whether that repeats this year is worth checking in the app rather than assuming, but it tells you something useful: this is a well-worn trip and the railroad plans for it.
Two stations on the line, Breakneck Ridge and Manitou, are request stops built for hikers, and only certain cars open there. Ask the conductor when you board. Trail conditions and closures in the Highlands change, so check the state park's current status before you plan a hike around a specific summit rather than turning up and hoping.
What follows is how we'd rank the four realistic stops, based on what you actually want out of the day.