Horten is a city in Vestfold, Norway. It is famous for being the only norwegian city to have been visited by Bob Marley, back in 1978.
North towards Oslo
It is advisable to get to E 18. From Horten you have to head towards a settlement kalled Nykirke. If you follow the 310 road (from Horten) you will get there and eventually to where the E 18 begins. This intersection is called Kopstadkrysset. If heading north, you stay in the same side as the petrol station (Statoil). You can either ask at the station or go where the road slopes a little and goes in to E 18. This is a good spot, as you have a bus stop just before the motorway begins.
South towards Skien
In Kopstadkrysset (see above), you cross to the other side via the bridge. When you cross the bridge you see a roundabout. Here is a blue sign named "E18 Larvik Kristiansand". Here you can also hitchhike, as cars can stop just before entering E 18.
Alternative information: Sleep, Food, Things to do, etc..
Horten has ferry link with Moss, so you can easily cross the Oslofjord.