In February, you should expect the entire mountain to be open, including the glades. Being as this is PA, you should never *expect* everything to be open at any time of the season
As for going to Hidden Valley...nah, not worth it. HV is flat, composed of more runouts than skiable terrain and has nothing of any steepness to it. It's blacks are blues at best and the pitches very short. Not that any blacks around here are true blacks, but it's definitely worse at HV.
North face is 98% of the time, the place to be. The exception to that rule is if it's stupid cold with howling winds that day...then the NF can be rude. If it's a fresh snow day, there's plenty of "places to be"...but I'm not giving those away publicly on the web
February is a good time to visit.