It's not far from Kyoto city, just 10Km. also it's 15min walk from Arashiyama station. We had may be 20 min hike up to the top. It was really stunning view from top of it. You can see the Kyoto from here. Monkeys are really nice. You don't have to panic. It's totally safe, just in case the warden always keep an eye on you as well as monkeys. Really good experience. you can buy tickets from the bottom of park. We didn't have a pre-booking.