Re: your comment about having to wait a year to return there was an article last year with a plan to use cargo ships to move the necessary supplies to Mars before the Astronauts got there. The cargo ships would use a version of VASIMR also but the transit time would be much longer. Speed wouldn’t be a consideration.
I believe one of our former astronauts has proposed using a series of ships left in orbits that cross paths of both earth and mars to haul cargo.
Not exactly overnight express but an interesting idea none the less.