Are CV or Timberline going to be packed on MLK weekend....particularly Sunday and Monday? Does Timberline have big lift lines since it only has 2 summit lifts?

To put it vaguely, in a river guide sort of manner: it varies.

I'm not the best qualified to reply, but here's some educated guesses.
If conditions remain marginal, you shouldn't have crowd trouble at either place. If conditions dramatically improve just before MLK day (and hopefully they will), crowds will spike, but Monday should be lighter than Sunday. I think of the two, CV tends to absorb crowds better. If you have the luxury of deciding which to visit each morning, they are close enough to visually inspect before buying lift tics. These two are generally less crowded than many other mid-Atlantic ski areas regardless of the day, so I'd be bold and go for it. The CV area is beautiful.

I have been skiing at CV for the part 4 or 5 MLK days (Monday), and have yet to experience much of any lift lines at all. (Based on my past experience) I would recomend going to CV (although I do not know what Timberline is like on MLK day.)

According to another thread on this msg board (http://www.dcski.com/ubb/Forum1/HTML/000611.html) Timberline had some fairly lengthy lift lines over MLK weekend, while lines at CV ski area were much better.