This section predominantly features walking along country lanes through a living and varied Roslagen landscape. After Roslagsbro the trail skirts Brosjön lake before reaching Bro Väsby.
Approximately 400 metres from the trail is the bird-watching tower on Brosjön, one of the best lakes for water birds in the county. Brosjön is rich in nutrients, with many species of water plants. Of particular value are the cultivated coastal meadows and pastures, Brosjöns flora and fauna and the river, Järsöströmmen, with its clean, clear water and unique invertebrate wildlife.
Between Brölunda and Vik the Roslagsleden trail passes a waterfall, Kvarnfallet. There was once a mill here. The watercourse used to flow in the valley below the road down to the bay Norrtäljeviken. This is where Viksbåten, a unique boat from the Viking period, was found. A church bell, now in the Museum of National Antiquities in Stockholm, was also found here.
Viksbåten, which dates from the 11th century, can be seen at Erikskulle Folk Museum, about 300 metres from the trail. Taking Skansen as its model, this open air museum was founded in 1919 and contains buildings and thousands of objects from Söderbykarl and the surrounding parishes. After Skansen, Erikskulle is the oldest and largest open air museum in the county of Stockholm.
On the western shore of Rådasjön lake there's a jetty for swimming and a dry toilet, changing hut and a car park. This section ends at Bagghus bridge near Gåsvik, the start of the Väddö canal.