It's simple to get there. The possibilities are the car, rail or even plane. Your destination you have to reach is Gothenburg.
The main airport is located in Gothenburg/Landvetter.
From there you can take the bus-shuttle to the railway-station in Gothenburg.
It's possible to take an earlier bus stop in the City, too.
You can reach the trail with bus or train from Gothenburg Central Station.
At these points you can get on the trail:
The bold marked ones are better to reach.
And here are the links for the timetables:
Resplus - Timetables for bus/train Gothenburg/Landvetter/Strömstad
Västtrafik - Timetables for buses around the Bohusleden
