Work at all 3 Jobs in New Ark, Gentlemen's Club, Diner, The Rock.
Go to the Managers that Hired you after meeting Alissa, trying to be a Bandit again in abandoned Town, talk to her in the Safehouse, Use all available Dialouge, then she would want to be useful to Cassie.
To meet her as a Bandit wander around the Town till you get her again.
Then after she fails all Jobs use the Hypnosis Treatment, at Transylvania, simply ask Rinny, if it will help Alissa.
After this Sleep somewhere else Except transylvania, only after a few days Rinny, would Move from her postion to the Dungeon, where you will see her playing with Alissa!
No Fighting in this Quest so you wont need to Prepare anything really.