Thanks for the recommendation! I don't know what I did but I just textured a track segment perfectly within 10 seconds. There must be magic involved. Edit: I made a video about it: http://www.youtube.com/watch?v=_E0k-t5qEEg

Thank you very much, Pilou! Apart from Zorro I think I'll be better off doing these tasks as I'm used to but those plugins are helpful nonetheless.

The method texturepath = material.texture.filename returns the path/name of the material's texture's image-file. Use something like imagename = nil; imagename = File.basename(material.texture.filename) if material.texture... To change a material's texture you use a new path material.texture="C:/.../mytetxure.png". To get a material's name use matname = material.name. To rename a material use material.name="newname" OR material.name=imagename if imagename - note that the renaming method is unavailable in older versions of Sketchup...