We live in Fairfax, which also has the same school break days this year. Last year, my sons (12, 9, and 6) and I used the school break time to go to Wisp to learn to ski. I was surprised at the number of other families who had traveled there from Fairfax County. The beginner area, in particular, seemed very crowded to me, though we had no problem getting rooms in the lodge at fairly short notice.
We had a much better time several weeks later at Bryce, on a Saturday. We left very early and got there when it opened. It's a two-hour drive, which may be a bit more than most people want to go for a day trip, but it was delightfully uncrowded and we were all able to ski down the green runs (and one blue) by the end of the day. (OK, so we cheated and left the six year old at home). I would definitely try Bryce again.
My only experience with Whitetail was a failed attempt to ski on MLK day last year. Too many other people had the same idea, and even though we got there early, they ran out of children's rental skis before we got to the rental window (but after we had paid and waited in line in the cold for an hour). We now have some free lift passes to Whitetail, which we will try some weekday.