...if you can't do a Mars orbit rendezvous you have no business going to Mars.Got me thinking. To reduce the cost of mars missions most things should not travel with the colonists. They should either be waiting in orbit or on the surface. However, safety requires some redundancy of things that do travel with the colonists.
We can put things on the surface of mars with a certain amount of accuracy (going up) and cost (going down.) Before they learn to live on mars ISRU we can keep dozens alive on the surface indefinitely (although healthy is debatable we shouldn't be afraid to find out directly and deal with it. Not going is not an option.)
People going to mars initially should be planning for a one way trip. This doesn't mean they never come home. It just means getting them home is a different mission for sometime in the future. They should go with the intent to settle or not go at all.
For best results we should be generous in over supplying them and getting enough hands on the surface to do meaningful work. My proposal is a dozen researchers on the first trip followed by several dozen on the second trip. First job, setting up their habitats and power. Second job, water ISRU and agriculture. Once they can produce enough food, water, air and power the next wave of colonists can follow.
These researcher start out in earth orbit in two ships that need refueling.* Mars landers have been sent ahead and wait in mars orbit. Resupply can also be waiting in mars orbit so the missions have some flexibility and margin of safety. The mars landers should also be reusable accent vehicles but that isn't essential.
By sending everything we can ahead using the least costly route and planning for a one way mission we can move toward mars settlement much faster than some paralysis by analysis methods. Looking before we leap is smart, but not taking the leap at all is not.
Update: *The ships start in orbit needing refueling. The passenger go to orbit when the ships are fueled and ready to go. There would likely be an exchange of astronauts. Those refueling the ships return to earth while others go to mars.