tux67
As this is a marked trail, I would expect the X4 painted on close to every 2nd tree on the way. 
We usually map Guideposts and Information Boards like you mentioned above. See: https://wiki.openstreetmap.org/wiki/Hiking#Infrastructure
All the single painted signs will be not mapped. That the reason why we map  the whole route as a hiking relation.

https://wiki.openstreetmap.org/wiki/Hiking#Tagging_walking_and_hiking_Route_Networks