The common sense way to explore Mars is to send robots first, to prepare the place for habitation. The first robot should be a nuclear tunneling robot, that slowly and methodically mines into a vertical cliff face. For about 100 feet, at intervals it drills holes and inserts reinforcing rods in the ceiling.
Since it is on a “one way trip”, its landing craft can be cannibalized to provide pressure doors for the entrance of the tunnel, as well as pre-wired flooring, walls and ceiling.
At the end of the tunnel the tunneling robot digs large cisterns for storage of water and sewage in bladders. If the astronauts have a pressurized environment with water and electrical power from the nuclear powered robot, they will be able to quadruple the amount of time them spend on Mars.
And when they leave, the robots go back to work, continuing to improve the situation. So that with each visit, colonization becomes more possible.
I totally don't disbelieve the possibility that our being on earth is the result of terra-farming.