regarding the markings on the road the way of st James goes this way to the bridge

This is an isolated dwelling - there should be a landuse=residential around, not just farmland.

On the ground in the very center of the tower is a triangulation point. Since I don't know if the mapped tower or the mapped triangulation point are more exact I just write this note for people which know the whereabouts better.

here is a path with steps (see uploaded log)

Around here - the first driveway to the west on this part of D94 - is an organic farm with a shop open from 16:30 on vendredi.

Check if this highway exists and if yes: how it crosses the railway. Bing Imagery doesn't show much helpful things.

Somewhere around here is a building which a hut not open to the public but with a quite extended roof which serves as good weather shelter.

the abandoned railway continues quite some distance upstream Le Lot