If you come from central Europe, we recommend travelling along the E6 motorway, which goes from Malmö in southern Sweden along the west coast to Gothenburg and continues to Oslo in Norway. In Ljungskile you leave the E6 and follow way 174 all the way to Bengtsfors.
If your route leads through Hamburg, we recommend taking the Ferry in Puttgarden to Rødby, Denmark. From Berlin the fastest way usually is Rostock - Gedser, Denmark or Rostock Trelleborg, Sweden. From Denmark you will either take the bridge from Copenhagen to Malmö or the ferry Helsingør (DK) - Helsingborg (SE). In some cases it can be suitable to take the longer ferries (over night) from either Kiel to Gothenburg or Lübeck - Malmö.