maybe i'm tripping, but it looks like Timberline is open Saturday and Sunday:http://www.timberlinelodge.com/ski_ride/conditions.php
of course one could pick up the phone and call 'em to find out if/when they are open/opening...
i've found the general rule of thumb, however, at least here in Tahoe, is Thanksgiving. That's the target date. If resorts open prior to that they're stoked. if they open later than that they're bummed.
we don't really seem to have the rivalry that Loveland and A-Basin have in terms of being the first resorts to open, even if it's with a WROD.
currently I believe the earliest opening date here is mid-November, but after being in Tahoe last weekend they'll need some serious dumps and drops in temps for that to be a reality.