If you want to explore the neighborhood, here are two nice options.
Why not discover the area around Oslofjord Convention Center. The route is 4 km long. If you want a longer walk, the route which includes Melsom VGS is 7 km:
An other walk is a coast walk to Rakkevik. This is a 4 km walk. If you want a longer walk, Storevahr is 7 km and a good choice:
You can also downloade UT.no app. This is Norways most popular hiking app! Use the links under.