I have to agree with Snowcone on skiing before the third week of December in this region. Timberline does not even try to compete for an early season opening. Instead, it generally opens on the third week of December, usually with 2-3 trails top to bottom. White Lightning is always first, followed by Salamander, followed by Dew Drop. Sally is a tough slope to cover so if temps are warm, it takes the resort a long time to get Sally finished and move equipment to other trails.
Snowshoe always works on the Basin first, then Silver Creek, and last but not least, Western Territory.
7 Springs focuses on Wagner and Stowe and then North Face Slope.
Your best bets for early season skiing are Snowshoe, 7 Springs, and Wisp--colder west of the Allegheny Front air + robust snowmaking = the best bet for early season action.
I went to 7 Springs on 9 December of last season and had a blast:http://www.dcski.com/articles/view_article.php?article_id=350&mode=headlines