Wiring to roof accessories

[brislex]

I'm looking to mount lights/cameras on the front bar of a roof rack, on a 2003 Berlingo Multispace with the full length sunroof.

Any suggestions as to the best way to get wiring to the front right side of the roof rack?

I've had a search for roof wiring on this forum but couldn't see anything. I could go out the aerial hole but this leaves the wires running a long way across the roof. Most of the amber beacon mount pics I can find are on hardtop vans.

Does anyone know a nice way of getting wires out of the drivers door (or sliding door)?

Has anyone done something similar with photos? 

How hard is it to drill a hole in the roof of a Berlingo?