I’ve already learnt the schedule of don’s men at the uhh... sex dungeon place I somehow forgot the name of from an NPC, but I can’t talk to her about it more or take her there with me.
So there also someone else at new ark slums that you can talk to. SHE can help you. After that you can talk to someone that HATES Don which will then lead you talk to some hobos at the slums. Be sure to read the dialog and rescue Cassie's notes to get an idea of what to do.