Skated a similar route to Ian but kept going on Ridge to the first intersection with 24. Skating was relatively easy on a slushy layer over a hard icy base. Ridge road was pretty dirty but improved a bit after I turned the corner at 1B. I assume the bench between the two ends of 24 was snow free but certainly think things would be skiable beyond.
On my return I opted to ski out past the lookouts. Champlain was mostly asphalt but I slipped by on a ribbon of snow. Long portage in front of Brule all the way back to Huron lookout. After that the return trip was fine although there were quite a few spots where you could see the yellow line through the ice. Got back just before the next drizzly rain started so I timed things well.
Warm and sunny tomorrow should start to open up the portages on the parkways. P12 might be a spot to try if you're determined to get one more ski.