User blog comment:Mesmermann/Game of Thrones, Comic Con Panel 2012/@comment-1788837-20120718224413/@comment-210608-20120722131001

Suddenly the isolation of the Jon Snow storyline from everything else seems like a boon!

They saved Iceland until last for season 2 filming so I assume they were already doing that again for season 3. With regard to the stuff on sound stages I imagine they will have to condense shooting Jon's stuff into later in the schedule now. It will take some reorganizing probably but it seems very possible to work around it and they have released a statement saying that it won't affect filming (as The Dragon Demands already said).