I agree with Ms. Brocco that without definitive starting & destination points that a precise response is unlikely and with Mr. Honeycutt that Google maps is an alternative source for vehicular access. I can add that Coach USA provides limited service between NY Port Authority on 42nd St and West Point, Visitor's Center on a daily basis at http://www.coachusa.com.
If you needed additional travel times, service is more frequent from Newburgh. You'd need to add about 20 min. subway travel from any of the 145th St stops in east & west Harlem. An added resource would be to go to http://www.hopstop.com,
which will provide public transportation information for NYC, commuter, taxi and foot transportation by inputting start and end adresses and will display approximate travel time according to time of day and inclusive of any service re-routing or service interruptions. The site also provides the options of sending the directions to you via email or cellphone text message.I hope this helps you.