Take your time and enjoy your surroundings.
It all depends on what you consider the BCF. The Great Bangor City Forest Adventure and Cool Tools will take some time alone and will bring you out to the Board Walk. There are many others out there too that are not that easy to find.
Take your time and enjoy your surroundings. If you start early enough it can be done but rushing through them might take away from the experience of the forest. To me anyway. The BCF Adventure is said to be about 7 miles to just complete that series.
More than one day is my recommendation. The trick will be to find two good days or more to enjoy it.
I have no enemies, but I'm intensely disliked by my friends.