MARS
2) TERRAFORMING
1) MARS
3) MARS CLIPPERS
4) FUSION DRIVES
The ultimate ships to Mars will not be chemically propelled, use nuclear electric drives, or be cycling stations with mag and solar sails or beam riders-they will be propelled by thermonuclear fusion.  Antimatter will probably always be too expensive and too hazardous.
INTERPLANETARY TRADE TRIANGLE
5) ROBOTIC MARS DIRECT