It seems like Kellan Lutz made an off-handed comment that might indicate that the vampires will be done filming in Vancouver shortly. Given that the majority of the Cullens are only present in the very beginning and the very end of the novel, the story seems probable. Given the re-arrival of Edi Gathegi and Rachelle Lefevere and since Cristian Serratos on her blog confirmed that the humans are also done filming, it looks like filming is clipping along at a productive and efficient pace. Also, since New Moon has a lot more interiors than Twilight, and the vampires are less in it, its far less weather dependent.
This also means that they are free for other projects such as PR appearances at film festivals, or shooting schedules of other features.
See Robessed for the details pulled together from several sources.