If you are talking about the foliage then it is mother nature, really cannot predict what you will get during your travel.
Only thing I can say is that if you happen to hit the place during the peak of the foliage and happened to be a weekend, then traffic will be very heavy and will take a lot longer to get to places (if weather of that day is nice). Wait for parking space can also be bad during a weekend at the peak of the foliage (again, especially if weather is nice that day).
Popular foliage locations can get very busy during the season, and can heavily dependent on the weather which you cannot predict in advance.