I'm reading the BIS magazine now and there's a great article about Apollo 17 and its celebration at Hollywood, last december.
I'll come back later to what Gene and Jack said, but Daniel Golding made an interesting speech too (that was weeks before Columbia):

"I believe that it is within the grasp of this nation, working with other countries, in no less and no more than ten years, to go to Mars.
We don't have to wait. It has nothing to do with health. It only has to do with how the american people feel about themselves. We don't have to be afraid, because there could be deaths along the way-and there could be. We should not be afraid, because if we are afraid of death in space, we shouldn't go into space. We are a country that has done incredible things. We will be on Mars. It has been thirty years since we left the Moon and in the next thirty years we will have expeditions, with people going to Mars, and perhaps even Europa, Jupiter's moon . We will land on asteroids and perhaps even comets. We will send spacecraft out of the solar system, to planets on other worlds, and without a doubt in the next thirty years, you will see astronauts on Mars"

I think we should start with a spacehab module with 2 astronauts in LEO (28°) spending a full year in space without any refurbishment from Earth all during that time.
When that succeeds, send the next crew to the Spacehab module ; also 2 astronauts to minimize the loads-one man and one woman (none ever went further than 600km Sullivan, Currie, and Thornton) and send them to a one year flight across the solar system (perigee Earth, apogee Mars or an asteroid). The very fact that they'd be so far away from Earth (even if the study of Mars isn't important-by then we'd know Mars much better than what the human eye can offer anyway) should be a major psychological factor to study.,They'd be flying by Mars, or perhaps turn once around it.
No large rocket nor big module would be needed. The major point would be to study what it's like to be so far away from Earth and the effects of an unprotected (no Van Allen belt) environment to the body.

Raoul