About mars...
Getting to Mars will be costly, I think this is how it should be done. This may take a while.
To get to Mars, with even a few people or a hundred requires money. Lots of money, billions of dollars. This can be made easier by turning this into an international project between the US, ESA, Canada, Japan, and maybe a few smaller countries. Then again this will come out of taxpayers butts. A smarter way of getting money, and opening space for exploration would be to have NASA share its experience with companies in the private sector and develop limited tourism in space. Over a ten year period the investment would have been recouped and enough money would have been made to take the burden off the people.
We'd have to set up a colony of at least 100 people on Mars to set up a very basic foundation. The best and biggest would be chosen which would have experience in lots of scientific and political science fields. Someone will have to be able to run some sort of grass roots government to keep them together.
People went to the New World not because of adventure, or even real estate it was because money could be made, i.e. loads of natural resources. This will have to be true on Mars, it may be romantic to think that all we need is a pioneering spirt, but we also need to make some money off this or it will become a black hole of the nation's cash. We'd have to set up a system of transporting precious metals such as platinum, titanium, gold, silver, diamonds and maybe even uranium back to Earth. There is plenty of iron ore down here, so we wouldn't buy it from Mars until our resources run out.
Once the colony has been set up, a small economy is formed than there should be further mining operations done on Mars. A widespread terraforming is a bad idea at the start, you don't want to invest billions and have it fail. A smarter idea would be to try terraforming a two or three mile stretch of sealed off canyon which could house thousands of colonists. If this worked for a few years, and enough scientific data was collected than we could begin terraforming.
Theres a small, and relatively unthough of of problem. Mars, at the fastest, is months from Earth. It would take longer to get there than it did for 18th century Britain to get to America. In simpler terms if there was a rebellion, it would be difficult to stop. This is why there must be a fairly stern governing system on Mars. Not harsh, but firm enough to not allow independence of the colony. After decades of Mars-Earth interaction Mars could have a huge effect on our economy, we don't want them itching for independence and throwing us into the Second Great Depression.
If we colonize and I believe we should we should do it, carefully, thoughtfully, and with the intention of spreading humanities seed throughout the Solar System for all of eternity.