The most recent guide book is Walking the Southern Upland Way Cicerone 2018, updated by Ronald Turnbull. This is available online, at larger libraries, and good book shops. It covers all aspects of the route, from local history, guidance and advice.
Another useful item to help with planning is the Southern Upland Way Map, Harvey Maps 2018, which covers the entire route on one piece of waterproof paper.
And just for fun, The Secret Coast to Coast by Andrew Bowden
The Southern Upland Way Rangers are also happy to help anyone struggling to plan their journey. Call or email for some local knowledge and we’ll get back to you when we can.