When I cycled across Canada I took a OnGuard mini D and a Kryptonite Cable. My girlfriend carried a simple cable lock. Light enough for a long trip and should be enough to deter anything but the most determined bike thief, particularly as their unlikely to try to steal a bike from right outside the tent the owner is sleeping in. Also, you tend to find in Europe at least that people generally respect the sanctity of the campsite.
When I cycled across Canada I took a OnGuard mini D and a Kryptonite Cable. My girlfriend carried a simple cable lock. Light enough for a long trip and should be enough to deter anything but the most determined bike thief, particularly as their unlikely to try to steal a bike from right outside the tent the owner is sleeping in. Also, you tend to find in Europe at least that people generally respect the sanctity of the campsite.