I think the establishment of a permanent habitat on Mars is far more difficult than such planners are considering. In spite of dreams otherwise, the venture will be an energy hog and there is currently no known easily exploitable source of energy.
I hope otherwise, but what I have gleaned about space travel over the last 60 years tells me such a project is many decades away. At least for the early times, everything, that is everything, needed will need to be take along and cost of transporting a pound of material to Mars is fantastically expensive.
You ain't kidding. Look this topic is beyond the scope of a college football message board. But until we get a cheap (energetically) to get out of the earth's gravity well, nothing like this is happening.
Pointless stunt to send a human to Mars (and let's assume we planned to bring him back). Robots are going to be doing.... all the exploration and any other work in the solar system. Human's silly insistance on breathing and coming back from any mission, let alone having to account for food, poop, climate control, heavy radiation shielding...
Just not happening. My guess has been for a long time that the first human to step foot on Mars will find the equivalent of a five star hotel waiting for him to spend time in. It will be built remotely by robots, so why not make something nice?
As far as "colonizing" Mars, again until we have Space Elevators (conceptually they work, and we could probably build one - if we had materials that could actually compose the tether), we aren't sending four or five hundred people to Mars one Apollo type booster at a time.
If you want to get wonky, we could send as much sperm and ova as a doomsday package for safekeeping. Not sure how long that stuff keeps on ice, but it's something.
Or just do really complete DNA sequencing and have a data warehouse on Mars - or wherever at that point. Space Habitat, Moon,Moons of Jupiter, wherever really.
As far as that Space Elevator thing goes, it has been extensively studied. The math works, and they have even worked out construction techniques. As I said the problem is materials, materials that seem to be theoretically possible to make, though the timetable is anyone's guess. Anywhere from next year with some neat breakthrough, to fifty years or so on the outside.
My two cents.