Off-Earth Colonization?

Thinking about all the talk about colonizing Mars, has me thinking that we would need a lot more prep work than what is being mentioned.

• Supplies would need to be sent in advance and stockpiled.
  • Since self sustainability is unlikely, at least not without greenhouses, continuous supplies would have to be sent on a schedule.
• Robots capable of construction would need to be shipped early on to facilitate initial building of human habitable structures.
• Communications, particularly relays would need to be established immediately.
• Some sort of escape plan, equipment, and vessel/ship would need to be in place (possibly the ship used to arrive.)

Not sure the costs would be worth it with our current abilities.

Just a few random thoughts…