Do you plan on replacing the wire all the way back to the load center? Does your cabin have a fabric headliner? Pictures would help.
My 86 O'Day 222 has a fabric liner and the wires are buried under it throughout the cabin. They're still like new but there is no way I could ever replace them without tearing out the liner.
With that said though, years ago when I lost my mast out off Newport, I had a new mast made up with a whole lot of changes including a steaming light installed 2/3s of the way up the mast, a foolish decision I regret to this day. This meant having to run one or two extra wires to feed my mast lights. I had already run a coaxial cable from the VHF radio to a thru-hull coax fitting near my mast tabernacle anyway, so two more conductors wouldn't make that much more difference.
What I'm implying is that if you need to run wires in the later model O'Days with headliners, you're better off leaving the old conductors in place and running your new wires via a route less conspicuous like the upper inside edge of the settees, or behind bolsters.
I could probably go back to my existing wiring to feed my mast as I had removed my steaming light several years ago. Two years ago I removed the two hideous looking dome lights in my cabin and went to self contained LED lights. I didn't want to cut the red and black feed wires to these lights so I took a Phillips screwdriver and stuck it in under the head liner along side of the conductors to separate the glued head liner and create a small pocket to hide the wires and this worked out great. Believe me, those wires are glued under that headline and there's no way to remove them.
If you can't get at the wires to extend them or do what you need to do, you're better off running wires from a different route.
If you think you can access them by removing a wood panel, look for a way of removing that panel without removing too much of it. Try to find the bungs which are hiding the screws to it.
Several years ago I removed every piece of wood from inside my cabin to stain and varnish it. There are ways of removing the wood without taking it apart piece by piece and having to replace all the bungs. I was able to do this by carefully examining it and coming up with a way of removing large pieces of it. This is probably what you may need to do.
I don't have a 23 so I really can't offer you the answers that you seek, but when I was working on my O'Day 222 I didn't know of anyone who owned one that knew any more than I did about how it was put together. All I can say is good luck!
Joe
