How I work out the route taken medieval pilgrims.
Firstly, my initial research has confirmed that pilgrims walked from A to B; be it a holy place or shrine in medieval times. I often visit the site to see what I can find on the ground. Often I cycle between the two points to get a general feel of the area and see what lies between. Then I do more research into the places along the route - the churches, historical buildings, religious ruins and names on the map.
Wherever possible I use public rights of way and use roads/lanes as a link to the footpaths.