If private enterprise is going to do this, to save a ton of money and inconvenience, it is best that they first send nuclear powered tunneling robots. Pretty much existing and ordinary technology.
This allows them to avoid much of the cosmic and enhanced radiation on the surface, vacuum, extremes of heat and cold, and the very abrasive Lunar dust; it makes their missions cumulative, so that every mission can bring more new equipment and supplies; and the more they tunnel, the more they can do. Plus, much can be done before people arrive and after they leave. Finally, when the people are there, they will have abundant energy for heat, air and water, powered by the nuclear power of the robot.
Because it is cumulative, the more they do, the more they can do. Eventually even building a launch site for other space missions of all sorts.
I went to Walmart to look for these the other day and couldnt find any. By nuclear powered do you mean radiothermionic generator powered or nuclear reactor powered. maybe I looked in the wrong department.