I haven't skied the highlands, but over at Nubs and can see across the valley they have been making a lot of snow in the areas that aren't open yet, they just didn't get enough in to open up North Peak & the Valley areas for Christmas week, but they should be open by next weekend, if not this weekend. Its finally gotten consisently cold, and finally getting some natural snow as well.
The past couple of years, the Highlands hasn't been running the Valley lift or even sometimes even the North Peak area midweek.
I skied the Highlands Friday, Sunday, and Monday (today). The front side is open from Camelot over to Amy's Run with the exception of the terrain park under the Challenger lift. Challenger runs were closed due to racing, but that's over.
North Peak is open, but I didn't make it there. Runs serviced by the Valley lift are not open yet, but probably will be soon. The Valley lift rarely ran on weekdays the last couple of seasons, but the North Peak was usually operating every day. Can't predict what they'll do this season.
Conditions are generally good. Heather had been beaten up pretty badly by the racers by 9:15, but K2 and Olympic were in great shape. Rob Roy was a little bony. Snowmaking on Camelot made that run "interesting". All this can change day-to-day, but the season is ON so don't wait.
Overall, Nubs is in better shape (skied there Saturday and most of last week) , as could be expected since they're more meticulous about their snowmaking and grooming. All the groomed runs are open and in excellent condition. A few glades are open and the bump runs and more glades should be open soon.
NOTE: The Highlands faces east, Nubs faces north and west, so I pick which to ski based on where the wind is coming from. Wind out of the west Friday, Sunday, and today favored the Highlands. Probably Nubs tomorrow.