I can see it in so many directions: femmeslash definitely, but also platonically where Sarah Jane mentors Rose (who clearly needs a professional direction), and I also keep thinking about the "somebody else's grandchildren" and ways that might play out.

Also, I'm a bad, bad person, but I have this irresistible mental image of Rose bringing Sarah Jane home to meet her mum. "But, Rose, she's older than I am," "Yeah, mum, but about 850 years younger than the Doctor."