Herkelås is the highest point of Tjøme with its 78 metres of height. For you, however, it will probably just be a small afternoon hike with a possible sitting on the top. You can see Oslofjord, Færder Lighthouse and Store Færder Island
On the top of Herkelås there are several burial sites from the Stone Age and Bronze Age. If you have the spirit of discovery, you can try to find Herkelåshula Cave. It was historically inhabited and is protected.