It's a beautiful place. Magnificent view of the Selim Bridge and the Bosphorus. There is a bus from the final stop of the Hadjiosman metro.
Below is the hospitable village of Garipche, where you can eat tasty and inexpensive food.
It is easy to get from Istanbul (1.5 hours by metro and bus). An amazing place! I really liked it! Be sure to climb up to the second fortress - a wonderful view will open! In general, I recommend you to visit!!