Berlin-based travelers can easily visit the Grumsin Forest in one day. The closest train station to the park is Angermünde (about an hour from Berlin Hauptbahnhof). Buses run hourly from there to Altkünkendorf town. The new visitor center in Altkünkendorf provides information on hikes, trails inside the forest.
Walking inside the forest is quite an experience, the type you read in German fairy tales. The forest is dark; some areas do not get sunshine.