Bill,
There is a dome light in the center of the hardtop on my 1980 43' DC that I can't get to work. I've toned it down the centerline rib in the underside of the hardtop to the fiberglass area over the windshshield. From there it tones over to the stbd about a foot and a half then fades out. Plans show that that cable should terminate at the area of the window wiper terminal block accessed through one of the access panels in the salon overhead. Wires for the wipers run from that TB up the stbd side of the center windshield. However there is no tone there for the dome light. Unfortunately, I've not had a chance to really look into it.
In short, I suspect that there is a channel in the center line rib of the hardtop running fore and aft. The channel enters the fiberglass area at the forward end of the hardtop and wires could be run to the stbd side of the center windshield then down a windshield channel to the ceiling in the salon. From there, you could get into the cable runs for the steering station. You could start by checking out the center dome light in your hardtop, if you have one.
Let me know if you have any luck. Someday, I'd like to move my stern light up there from the transome (and get my dome light to work).
Will