Scotland's size is deceptive — distances look manageable on a map but single-track roads, ferries, and the general ruggedness of the terrain mean things take longer than expected, especially in the Highlands and islands.
Citylink buses cover most major routes and offer tourist passes. The Haggis Backpackers and Go Blue Banana services link youth hostels across the country. Train routes are limited but often spectacular — the West Highland Line in particular. Driving gives the most flexibility; back roads may be single-track with passing places, and petrol stations thin out considerably north of Inverness. Ferries from Oban, Mallaig, and Ullapool reach most of the western islands; CalMac runs the bulk of these services. Aberdeen has ferry connections to Orkney and Shetland.