Well folks I asked questions and got answers about doing a mirror tap............don't do it. It can get really ugly as that glass ceiling enclosure contains a camera, the spine running down the center contains several antennas, GPS, update, radio, etc., a mistake up there can get real expensive fast.
My plan is to stay away from that and take a look at the 12 VDC fuse box under the rear seat for switched power, or do what
@hydbob did for his dash cam, either way I'll use Bob's routing, although I may exit the A pillar and string across the visor using tiny ty-wraps to attach the RJ11 cord to the visor mounting points.
Got a pic of the rear fuse box...
lucidowners.com