Princeton?

Tarrytown is right on the Hudson, has some good restaurants and interesting historical sites. Don't know about a spa.

I think you are a little confused.

The subway is only WITHIN nyc - it doesn't go anyplace outside of the city.

And one hour from the city by train is still the suburbs - from which many people commute on a daily basis.

Tarrytown is about 50 minutes - but you will need a cab or car to get to the type of lodging you are looking for.

Princeton is about an hour when the trains are running a full schedule - which they aren't at this point. Not sure when you are planning this trip - but presumably the trains will be back to a full schedule by then. Again, you will need a cab or car to get to appropriate lodgings (many nearby are basic tourist or business hotels - not the sort of inn-type place you seem to be looking for.)

You would have a lot more choices if you were willing to travel farther into the country rather than the suburbs.

Cold Spring on Metro North

Cold Spring is a really lovely little town.

Cold Spring is indeed a cute little town - and only about 20 minutes past you one hour limit.

Thanks, everyone! I will check out Cold Spring and Tarrytown!

Found Tarytown House - looks PERFECT! Red Door Spa at nearby mall, Sleepy Hollow, Lyndhurst Estate, nice local restaurants... You guys are awesome! Thanks.

what time of year are you planning on going?

From Nov through April the countryside won't be much to look at - and sights may be open shorter hours.

Kykuit, the John D. Rockefeller estate is nearby, with Nelson Rockefeller's art collection.

When staying or passing thru Tarrytown, we often stop here for lunch. if you like greek, this place has it going on. Hardworking friendly people. We usually share a platter or two, depending how many of us there is. Always take home a jar of their dressing.

http://www.lefterisgyro.com/Default.aspx?location=LF1

Check your dates to see if anything interesting is going on at the Tarrytown Music Hall

For sites in and around Tarrytown
check out this website:

http://www.hudsonvalley.org/historic-sites

Many of these sites are not open all year round. If you are going before the end of December some may still be open, others are closed until the spring.
In any event you will need a car or a taxi service to take you from one site to another

Sleepy Hollow is the name of a community, formerly known as North Tarrytown.