I really recommend using the trains in Scotland, as they're a great stress-free way to travel the country. I even left my iPod on the train in Stirling, and the conductor personally brought it back to me from Edinburgh.

ScotRail

The rover passes are a great deal, as they include some buses and ferries with the price. I got off a little better with a student discount, but they're still not too expensive considering what you get.

Enjoy the trip!