I did a lap of the south loop at Illiniwek with the CX skis yesterday morning and the trails have largely been packed by hikers and snowshoers. There is a 2-3" base of snow in most areas. Conditions look prime for some snow fat biking and weren't too bad for skiing. I didn't check the north loop but it probably has similar conditions judging from the boot/snowshoe tracks leading out of the north climbs.

Also, a few cross country ski tracks have been established in the lower fields off of IL-84. There may be a few loops in the campground area as well (if not there will be soon). I was able to squeeze out ~6 miles of ski-able trail between singletrack and the field loops with minimal retracing.

Hit the trails sooner than later because it looks like a thaw is coming Saturday and will probably turn the snow conditions to ice.