There is a gate on the mountain road up from Tsuru-tsuru Onsen but it is possible to pass through. The road up is generally good but with a few rocks and potholes. Once at the top the views are good but they have recently cut down a section of trees. On foot, follow the hiking trail c200m and you will be blessed with a fantastic view of a huge section of the Kanto plain. Definitely worth the hard work!