U-boot museum
Near the disused ferry terminal. perhaps surprisingly, the u-boat submarine on display is a former british submarine, h.m.s. otus of the "oberon" class, which was towed to sassnitz after having been saved from a scrapyard in portsmouth gb.
Take a bus to Kap Arkona. A change of bus may be necessary in Altenkirken, although the driver may confuse passengers by simply changing the number of the bus they are on.
craft centre
There is an extensive craft centre near the bus terminus in Putgarten. It is about 2 km walk to the Kap, where there is a lighthouse museum.