See website: http://home.tiscalinet.de/ockier/harz1.htm. Large Nature Park area South East of Hannover. Many climbing areas throughout region. Divided into West & East (Ost) Harz. Some areas were formerly closed in GDR days. Discreet forest camping possible for the adventurous. Otherwise, pay camping & hotels few & far between. Schierke or Oker are good villages to begin from. Marienwand [pictured], said to be most popular, is upriver from Oker.
In Schierke consider Hotel Konig: www.harz-hotel-koenig.de. Can leave car in hotel lot and walk 2 blocks to catch "Hexenexpress" [3DM] tourist trolley that runs to train station @ top of hill. Rock is in forest across from train station, within 100m. Otherwise, it's a very long hike uphill from the village.