In order to go to Mars, and come back quickly and safely, it would make sense to send supplies of various sorts on a robotic mission (or a number of them). This way there would be plenty of fuel on Mars.

Another possibility would be having a launchpad in Earth orbit, so that many different modules would be assembled (a lot like the ISS), but in a configuration that's designed to travel to Mars. Launching it all at once from Earth does not seem like the safest or most efficient answer to getting a very large mission payload into space, given current technology. This way, there would be allowances for failed launches, while the human crew is brought into orbit using more tried and tested methods (with sufficient rescue mission planning), on a much smaller budget than the whole mission cost.

Some kind of Exploratory Space Station seems like the way to do it.