Another board dealt with. This one was tricky - I forgot to cut a hole for a back box before staining and lacquering it, so had to put painter's tape on it so I could mark the cut-out, and then cut it carefully with a fine-toothed jigsaw blade so I didn't wreck the finish. Then trimmed a whisker off the end so it matched the angle of the corner post (since the house is 100+ years old nothing is quite square), and got the socket wired and tested.
My boards aren't long enough to cover the entire length so I matched another piece as best I could based on size and grain pattern. It's now cut ever so slightly oversize so I can match the ends that join, then prune half an inch or so off the end that butts against the door trim. The join will be visible but not hideously so and there's a good chance it will be behind a dresser anyway.
It was a real pain getting my miter saw up into that room and it's a hassle trying to move it around so I can cut boards from an appropriate direction, but it has made it so much easier getting things cut to size.
Now I just have one piece of board I need to cut to size, edge and finish, and another wall to deal with. But at least now the end is in sight, which is always a good feeling.