We should distinguish between:
spontaneous acts, those proceeding from an internal principle (e.g. the growth of plants and impulsive movements of animals);
voluntary acts in a wide sense, those proceeding from an internal principle with apprehension of an end (e.g. all conscious desires); and, finally
those voluntary in the strict sense, that is, deliberate or free acts.
Am I to understand that under Reformed doctrine that man can only commit acts of spontaneity (ie God providing the entire inner principle of action and man CANNOT do any other), or does man have the ABILITY to commit acts only with that apprehension of an end (ie towards either heaven (if elect) or hell (if non elect)), but not voluntary in the strict sense of free will that man deliberately chooses specific actions freely?
Let me answer your question by asking you a question; what choice do you think that man, as a free agent capable of choosing specific actions would make if given the choice of heaven or hell? Put another way, if God lined everyone up in the Garden of Eden and told each person, "Don't eat the fruit.", do you think there would be some in the crowd that would heed what God said? Do you think that you are far more capable of making a better decision than Adam who was perfect man? Yet that is what you are saying.
It's the way in which we have been created. We will all take that fruit because we want it. Adam was perfect but we can get down on him. We would make the exact same choice. 100% of the time.