text: I would only map it if it's the only way or really, really helpful or visually endorsed as a path/footway. In most cases it's probably not necessary, since it's not really relevant for routing purposes. Feel free to read through a few older discussions about this: https://wiki.openstreetmap.org/wiki/Tag:natural%3Dbeach#Mapping_path.2Ftrack_using_beach_as_its_part
  
  Either way "natural=sand" should not be on that way, it's meant for areas that are nothing but sand. surface=sand is good enough.