Google up on articles on the Lazarus Doctor (he works on patients who have nominally died of hypothermia) and on the new experimental saline blood substitute for potentially fatal injuries (the paramedics swap the patient's blood for the solution, deep-freeze the patient and reverse the process at hospital, eliminating all stress and trauma to the body in transit).
The theoretical duration you can perform suspended animation in real life is unknown, but is estimated to be many months.
The practical duration is only a few hours, so far.
The cost of improving on the practical duration (since the former method is really only limited by how long you can artificially keep O2 levels in the brain over 45%) is far, far less than the cost of a mission to Mars. Ergo, that is the logical solution. Fund medical research into the two methods. Put 100% of NASA funding for a manned Mars mission into those two techniques for at least the next couple of years.
That should accelerate development of the necessary technologies. By doing it this way, you need absolutely bugger all new rocketry technology. The N months food needed for the journey by live astronauts can be replaced with radiation shielding of the same total mass.
This leaves you with radiation on Mars. But only if you land on the surface. What you want to do is land in a deep narrow gorge or chasm. There are some, that is where the methane was reported. That increases the thickness of atmosphere, which is good for radiation. It is unexplored, which is even better. There is a chance of a cave network, absolutely ideal for looking for water, life and/or a good location for settlers.
Oh, and doing things this way improves life on Earth, the very thing all the anti-space people demand NASA prove they can do.
Everyone's happy, apart from, well, everyone. NASA doing a better job of health than the NIH will upset people. A workable mission will upset futurologists because the future will be done rather than talked about, putting them out of a job. Eliminating the radiation problem will infuriate the buggers who say the mission can't be done. Eliminating any issues with transit time mean you can launch the mission the day after the medical stuff is sorted, leaving those talking about a 2030-2050 timeframe looking as stupid as they really are.
So, yeah, it'll get the job done, but expect those involved in a mission to be lynched by a mob of respectable plutocrats.