Because of not working full time at first, Bob correctly did not anticipate much income. So Bob told them he'd have to keep his photo business going during the daytime to survive. They agreed, though if he had stayed in the program it was understood that he'd later go full time and have to get someone else to handle the photo lab. It was the same with the bus. I'd like to point out that we really have no idea when and how the others at S4 went to work.
Nothing indicates that they even had to live in Nevada.
They may have been flown in from California or New Mexico, or even stayed at the Test Site and only went to their respective homes in their respective states on weekends. Anyway, this is the reason for the unusually small numbers of people on the bus with Bob and Mariani. He also claims to have had a Q clearance so should be quite familiar with the requirements of working in a highly secret compartmentalized environment. Yet he easily violated all his signed agreements and oaths by freely disclosing information to his friends. I can post it again if you'd like.