Seeing it is not necessary to have an immense radiation shield on Mars, humans would not have to live underground or in a big rock. Instead, transparent domes could be built. Within these domes plants could grow and humans could live in a moderate environment. These domes would be made out of a hard plastic material similar to Kevlar by they would also have a plexiglas radiation shield around it. A dome created for humans to live in could not be any larger the 50 meters in diameter. If the domes were built any bigger than 50 meters in diameter, they would have a good chance of popping due to the weak pressure exposed on the open surface. Plant domes could be bigger, seeing that plants only require a pressure 5 times weaker then humans. Below is a graph where you can see how much a dome with a given diameter would weight.
People living on Mars may feel uncomfortable living their lives in Domes, never being able to go outside without a breathing apparatus, and depending on machines for the necessities of life. The first citizens of Mars will all be put there for a reason, and this group of elite humans will work to the best of their ability to make the colonization of Mars a success.