For both the Moon and Mars, and even the asteroids, why not have robots build and stock bases using as much of those world’s resources as possible.

They could build large bases. No need for small, cramp ones. They could have greenhouses with plants fully grown. Imagine humans getting there and having a fully functional and fully stocked base with lots of leg room.

We are talking about an army of robots capable of mining, refining, tooling and building. That 3-D printer might be the way to go. If we had something like that, which could build things using raw materials, anything could be built. Something like that is probably years away.

Still, I think it could be done with existing technology. The robots could be remote controlled from Earth, by humans. The hardest thing, I think, would be the refining material, and then making useful items out of it. The mining and actual building is probably the easiest part.