So we set out at 2:00 and headed north to the nearest winding, turned, and came back. No big deal, but very pleasant nonetheless.
Back at the marina, Grace used the wet vacuum cleaner we bought the other day to suck some of the spurious water out of the bilge under the cabin. I'd found a way to attach a narrow plastic pipe to the cleaner's tube, using a rubber doorstop, and Grace got a good amount of water out. We'll keep looking down the inspection hole to see if the level rises with the movement of the boat.