Gary H: I have actually answered your question in many of my cool image posts. The guidance we are using for where we send rovers today is entirely controlled by scientific concerns. The needs of future colonies is not the prime or even a driving force.

Eventually, as private concerns (such as SpaceX) get closer to launching their own missions, they will send out their own unmanned scouts to study exactly the issues you raise. I for one have already suggested one particular cave on Mars that merits further exploration prior to manned missions.

Surely people who study these things have words for all of this. There must be more of these ante/post glacial things than drag racing engines with cylinder ignition problems and we have a word for that.