Viking Way
From OpenStreetMap Wiki
This runs from Barton-upon-Humber through Lincolnshire to Oakham in Rutland. Relation
404079 (XML, check, manage, JOSM, history, view, gpx ) is being added for it. Bits and pieces have been added here and there, but there are still long unwalked sections.
An alternative section south from Lincoln is the Danelaw Way.