Not really a guide but a hint if you also have problems with the quest "The Queen Gambit" like me.
If the NPC goes back into the cave - just do 3 - 4 rebel missions afterwards. She should be in Lisoio automatically then.
Ubisoft is aware of this problem and want to fix it in the next patch.
There seems also to be a bug afterwards this, when you get on the horse with her (Thanks TheDude722!)
When I did Queen's Gambit, we got to the wounded bear and the game forced me off the horse. But the queen never got off. I had to reload my last autosave and then she finally tended to the bear.