"He is a Stark." Jon shares her concern for Ned, though for different reasons, as unfamiliar as he is with King's Landing. He knows that his presence at Winterfell is only tolerated because of Ned, and he doesn't know what it means for him if Ned leaves. Where does he end up? In truth, there's really only one place for people like him. He had always figured it would happen someday. It may just be sooner than expected. In the meantime, he just has to watch his father and his aunt (with whom he has a closer relationship than any of his siblings do) have their battle of wills and wait for the outcome.

"Robb will be lord of Winterfell while Father is away." It will be good practice for when he's lord of Winterfell in his own right. "I'm not sure what my place will be after this."