I don't really understand why there even is a 'Program Mode,' if anybody would like to explain that . . .
How does it differ from Auto?
Frankly, anybody who has a D600 should get to the Manual, Shutter Priority or Aperture Priority stage, from the very beginning. If you set auto ISO and auto WB, or play with either a bit, the D600 seems to cover a very wide range of exposures and situations if you experiment, bracket a bit, and really think it through.
Amateurs (being a long-time one myself) should not fear Manual, and should avoid using the settings which are like training wheels on a bicycle, unless for testing purposes, to see in tough lighting how to make it better by comparison. IMHO, of course.