I don't have a life anymore, this thing kills me --> 次回更新は2015/1/15です
Personally I think they are dating already. I don't really see many Japanese girls walking home with their hands like that (Correct me if I'm wrong, I'm such a shut-in). Also, I realise that Keiko didn't reject Ran's request to go home -visiting Keiko's mom-, whereas Keiko rejected and reasoned her close friend request to do so.
NOTE: THEY ARE SO CUTE...