I can only speak about St Williams. I went out today and it was tough going. Snow is getting to point that its almost too deep. Like I mentioned in a previous post the snow is semi solid. Meaning that you can float on top of it if lightweight and you keep your speed up. But once you slow a bit or start to break though the snow you can be screwed. Wheels start spinning and next thing you're bellied on the snow.
New thing today was all the slush. I popped my three holes in and the water shot up the holes by about 4". It would seem that all that snow on top is weighing/pressing the ice down. As soon as you puncture the ice, water comes up. And then the snow starts wicking the water and slush abounds. I was surprised how far the water/slush wicked from huts/holes.
So you want to stay on packed down trails to get around. But these trails often run near huts that now are making slush. Kind of damned if you do, damned if you don't.