The right of responsible access to land in Scotland is enschrined in law. You can legally hike, camp, cycle, and horse-ride over most land with one or two exceptions. You also have the right to sail and canoe on any stretch of water.
The exceptions are mainly based on common sense. Obviously you can't camp in someones front garden for example, or a military excersise area, or the Glenfarclas barrel room. :)