I drew this map of the Eastern Settlement (one of two communities in Norse Greenland, existing from roughly 985-1450) back in 2013 for an unrelated project. While not whatsoever perfect (or accurate!), someone reading “The Snowman of Bishops Fell” may at least get an idea as to the location of the action.
You’ll notice a cross labeled “Gardar” just above the separation between the images. This was the location of St. Nikolaus Cathedral (and the residence of the bishop). You may also imagine that one of the three mountainous triangles immediately to the right of that location is Bishops Fell.