Good choice
Old Bill: you have made a great choice. I single-hand my Oday 23 all the time. Here are my suggestions: leading the halyards back to the cockpit is ok, but in my humble opinion, not the best way to go. The single biggest improvement you can undertake that will make single handing an Oday 23 easy and enjoyable is to install roller furling. I did so after two or three seasons on my boat, and I can't believe I waited so long. Previously, I had put in a downhaul for the jib so I could dose the sail from the cockpit, but it never worked great; and even when it worked ok, I still had the sail flopping around on the foredeck. I also thought about bringing the main halyard back to the cockpit, but I realized that I would need to remount the winch on the cabin top, and there is precious little room to do so, not to mention that fitting a deck organizer in too would be a tight squeeze as well. Also, I would have needed to cut open the cabin liner in order to access the actual bottom of the coach roof (you can't just drill through both the coach roof and the cabin liner and bolt the winch and/or organizer from the inside of the liner; you have to remove the liner itself in that location so that the bottom of the roof is accessible).
For me, the hassle was never going to the mast, it was going on the foredeck. In a small boat, even small waves make the bow go up and down, and make handling the jib a challenge. And don't forget: even if you lead the jib halyard back to the cockpit, you still have to somehow tame that sail as it comes onto the deck. Roller furling is the way to go! I have the CDI and think it's the greatest thing since sliced bread.
Two other low cost single handing gizmos: the tiller tamer and Winchers. The tiller tamer will hold the 23 on course quite nicely; I have used it on reaches and had no need to touch the tiller for 20 minutes at a time. Others on this site have said less flattering things about it, while still others say that there are more robust versions out there. Winchers are those blue rubbery rings that fit over your existing winches and make them into a reasonable facsimile of a self-tailing winch. Like the Tiller Tamer, Winchers have their fans and their detractors. I have found them to be useful if not perfect. If nothing else, its easier and quicker to cleat a sheet off in the Wincher than to use the real cleat. Check the archives here for all of the various rants and raves for both the Tiller tamer and Winchers. If you still decide to lead the halyards aft, I know that several folks here have provided pictures of their projects. I have provided a link to one such set up. I know there are others too. Good luck!