4. The Crazy Archaeologist
Her appearances from Season 5 to 6 had suggested that the reason she has become an archaeologist was hugely because of the Doctor, if not the main, which later on was confirmed near the end of Season 6. The post-prison Dr. Song's adventures, we can assume, were more about exploring historical facts and looking for the Doctor's subtle (often times, glaring) signatures in them. It's presumed that she looks for him all the time, eager for their adventures to never end (which sadly, we know will). So how chaotically entertaining could that be? I would gamble at "very".