Okay, I replaced the chain, cleaned the rear and front derailleurs, and swapped in decent pedals. I trued the front and rear rims, repacked the front and rear hub bearings, and cleaned and lubricated the freewheel. Now, with the original bars and stem back in place, and cleaned Shimano brake lever hoods, I've taped the bar with inexpensive black faux carbon stuff that I had.
Now for a test ride this evening. If I decide to keep this, then there will be things to change on it. I'm not a fan of this shape of saddle. The stem reach is ~1cm too long, and I'd like to lower it a bit. Then, there's the question of shifters, cable stops, and freewheel. Maybe I'll reach some conclusions tonight. 42 x 24T doesn't scare me as a climbing gear, not with this sporty of a frame geometry.
EDIT: I know that the chain is 2 links too long. I'm waiting to monkey with that until I decide its future.