Two points on Mars colonization: bigger rockets are not the solution. And solar and galactic radiation is not your friend.
Getting stuff into space should be done using maglev/startram style shots with scramjet boosts at the apogee for the final push into LEO. High G, extreme velocity shots. People have to go slow, fragile as we are, so rockets are the only way there sure. But not for stuff. And most of the material we need in space to begin being a space faring species can take very high G. Quit building bigger rockets and build a smarter LEO launch system Musk!
Once there on Mars we need to tunnel. Where did the first mammals live when they evolved all those millions of years ago? Burrows. Get underground and you’ll be safe. Same goes for Mars. But on Mars the bad stuff isn’t going to eat you it’s going to poison you with radiation. Only dirt and rock (and water) will protect you from the massive radiation influx Martians will have to endure. So send tunneling machines first. Build the tunnels that will be the only true protection for humans once there.
So, yes, get humanity cached off planet on Mars (and the Moon), just in case you know. But get smarter about what really has to be done to do it.