How does 3 Base Accommodation work? - The Three Accommodation Bases instead of the usual En-route Accommodation option, is intended to provide more flexibility in daily walking distances (specifically in the central section of the Wall), for those who prefer not to have a set daily walking itinerary between their accommodations. However, this option is dependant on making use of the Hadrian's Wall AD122 Bus Shuttle service and is therefore restricted to the times and the route that this service runs on.
In effect, the Shuttle service operates between Heddon-on-the-Wall and Carlisle, with the main area of operation (in terms of bus frequency) between Hexham & Carlisle. The bus mainly follows the route of the Wall (generally close to the Trail) by way of Chollerford, Housesteads, Twice Brewed, Vindolanda, Haltwhistle, Roman Army Museum, Greenhead, Gilsland, Birdoswald, Lanercost, Brampton, Crosby and Carlisle - it does not operate near to the Trail on the section between Lanercost & Crosby-on-Eden (ie via Walton, Newtown or Irthington). Beyond that, the Shuttle Bus only functions during the main season, between Easter & the end of October.
For those choosing to come during the 'out-of-main-season' period (ie between November - early April), the only really practical option, is a one that follows an 'En-route' itinerary, walking between accommodations.