What I plan to do on my rando bike is into the steerer through the crown, out through a hole in the side of the steere in the mimimal stress axis, i.e. 3/9 o'clock, then loosley wrap around the steerer before going down the downtube, through BB shell then out a braze-on on the back of steerer.
You could exit at the bb-shell through a vent port and into a mudguard, or up seattube and out through top of seatpost to a saddle mounted light.
What I plan to do on my rando bike is into the steerer through the crown, out through a hole in the side of the steere in the mimimal stress axis, i.e. 3/9 o'clock, then loosley wrap around the steerer before going down the downtube, through BB shell then out a braze-on on the back of steerer.
You could exit at the bb-shell through a vent port and into a mudguard, or up seattube and out through top of seatpost to a saddle mounted light.
SEe these albums and the attachment for some fancy ideas for a ring commutator, but it touches on steerer drilling.
https://www.flickr.com/photos/21624415@N04/albums/72157710996851941
https://www.flickr.com/photos/21624415@N04/albums/72157674615273680/with/35129857301/