Svalbard and Jan Mayen Islands
Svalbard and Jan Mayen are an extraterritorial part of Norway.
Svalbard has the approximate size of Ireland, but almost no roads. There are only a few settlements, of which the main one is Longyearbyen. Even there, roads are almost just within the town. The exception is the 6 kilometer road to the airport, where also the camping site is located (as a hitchhiker, you usually stay there). On this road, hitchhiking is super easy, almost each car gives you a lift. But there is another, quite extraordinary possibility to hitchhike: Go to the airport and ask the crews whether they can give you a lift. Not sure they will, but once it worked. See also: Hitchhiking a plane
NOTE: It is common practice on the island for at least one of the hikers to carry a rifle and setup bear alarms when camping (outside the camping area). Rifles can be rented in town. Hiking without a rifle might result in a very expensive helicopter rescue.