re: Duration!
If a mission only lasted less than a month, many problems would be solved.
The issue of how long a mission lasts has many also unexpected consquences...
There'd be less radiation, less damage to the spacesuits from dust.
Less consequences from weightlessness, less need for comfort.
There'd be more flights within a timeframe (with more astronauts involved, therefore more experience, more witnesses).
There'd be more attention from the public (too long a flight and the public will get bored).
The Moon can offer this opportunity. For Mars, it's unrealistic to expect anything but a long duration flight.