This cache is part of the Moffat to Leadhills (M2L) series placed for the Caledonian Cachefest.
It won't surprise you to learn that National Cicle Network Route 74 (NCN 74) follows the M74 and A74 from Carlisle to Glasgow. In fact, much of the route was once the A74, with one carriageway of the road turned over to cycling when the new motorway was built alongside.
It's a fast and efficient passage from England to the Scottish central belt, particularly popular with Land's End to John O'Groats cyclists.