I did an analysis of sending a factory sent to a carbonaceous chondrite asteroid that builds a factory factory which builds a solar sail factory that sends solar sails back to Earth-Sun L1 to counter climate change.

The first thing in the decision tree is "do you send a crew?" and you're trading off the hard problem of teleoperating the thing (need a big advanced in autonomy) vs the hard problem of providing a habitat and liklihood that the crew doesn't come home. So yeah, sending bots ahead to build an environment is an option even on Mars. I think Wall-E.

If you're going that far though you might consider not sending intact humans at all and just sending the eggs and growing them out either artificially or in some other animal.

(I see the Ceres thing as being on the line to interstellar colonization whereas I don't see Mars as such. A likely intermediate step past that is doing something similar on an outer solar system or interstellar body, say, Titan or Pluto, powered by D-D fusion.)