The fastest and easiest way to colonize space is to advance cybernetics to being able to transfer a human brain into a machine one. At that point, you can custom-build any kind of machine body designed for pretty much any environment, saving the trouble of adapting to the new environment through genetics (messy, slow, difficult to test) or bringing the environment with you (terraforming, purpose-build earth-like facilities).

Good on the article for outlining a lot of the issues with this, though I don't think enough time was spent on the mental aspects. We're adapted to live in a certain environment - a different one with different, more boring light, minimal plants, extreme temperatures, no area to roam, etc., is most likely going to be a miserable experience for all involved.