It will cost roughly $15 to get you from Penn Station to Madison Avenue and 105 Street. A cheaper alternative is taking the subway.From Penn Station, you can take the uptown (northbound) #1, 2, or 3 subway lines (Red Line on the subway map) to Time Square, where a transfer can be made to the 42nd Street Shuttle (Black Line) to Grand Central.Transfer at Grand Central for the uptown (northbound) #6 train (Green Line on the subway map), which will take you from there to 103rd Street.At 103rd Street, exit the subway and follow the walking direction at the link below.http://maps.google.com/maps?f=d source=s��The fare on the subway is $2.25 each way ($4.50 round trip).I hope this information is very helpful.Good luckNative New Yorker
screw the taxi...just take the subway!