I think there is no more or less sensible way. The only way is the way that actually works. Right now non of the options are viable. Going to Mars won't make humanity interstellar species because there are much more serious issues to solve than just going there, starting with the lack of geomagnetic field. If we want to change that we need to build space stations with artificial gravity and geomagnetic field so that people living on it are safe. This is probably a better option than trying to go to a desert planet without geomagnetic field.