I appreciate the concept...but respectfully disagree that it's anything like settling out west or other previous frontiers. Settling in space would be more like trying to build a world-class city at the North Pole or the bottom of the ocean. We haven't done it because it makes ZERO sense.
Space is so absolutely hostile to human beings, I'm a bit surprised that Mars is still something of a goal...especially since it's not really a habitable planet. It seems we would be better served to focus energies on the means of space travel (beyond simple propulsion and known fuels) and think more about finding planets that can actually be friendly to human beings (existing earth-like atmosphere, water, resources, vegetation, etc.). If no such thing exists...and if we can't work around our current understanding of Physics, we're not going anywhere...and any movement beyond a quick "hi and bye" to Mars (like at the moon) is an exercise in futility for the most part.