Say... it's wide open right now.
From the vantage point of Whitetail's base area webcam, I really don't think you'd be able to distinguish a regular weekend crowd from a much larger holiday weekend crowd.
Expect the parking lot, lodge, and the main lifts (high-speed quad and beginner lifts) to be very crowded until at least 6 PM. After that, the crowds will probably diminish substantially. But it will still be much more crowded than the normal night skiing session.
Expect the trail conditions to be substantially degraded in the evening due to the high volume of skier/boarder traffic during the day and possible refreezing of snow if it was warm during the afternoon.
If the option is to not ski at all, I'd say go for it. Just set your expectations accordingly.
The upside of the huge holiday crowds (XMas, MLK and President's) is that they are a major source of income for the local areas; ie, they keep the areas fiscally sound (and open during the rest of the year).