If you are talking about long exposures, I would bring snacks, drinks, warm clothes, and a folding chair or two if you can manage. A cable release if your shutter doesn't have a way to be locked in the down position. A table of recommended exposures for night shots and a reciprocity failure adjustment chart for your film. Paper and pencil to take notes. I would also use a film with better reciprocity characteristics, though Tri-X is beautiful in night shots. Fuji Acros 100 or Kodak T-Max 100 are good choices.