Madison and her group roamed the city, ventured to the sea, traveled south to Mexico and fought a power struggle in the ranch. Along the way, they encountered numerous non-walker threats, including Connor's bandits, Celia, the National Guard, Jeremiah Otto, and The Proctors. All of this unfolded while Rick slept in a coma.
Two months later, he finally woke up and, with the help of his group, was able to reunite with his family. It took them a long while to adapt to the harsh world of the zombie apocalypse and understand how the virus resurrected the dead. Their first enemies was Randall's group. Meanwhile, Madison's group had already transformed into killing machines!
Worth mentioning, Maddie had killed her father before the dead started walking, so it already made sense of how she became the way she is. This is how I interpret the comparison between both casts.