According to a Telltale Games livestream, A New Day was originally going to start with Lee's group in the drug store fighting off walkers, following a non-linear storyline. The scene with Lee in the police car wasn't made until later when they decided against going out of chronological order.
In addition, some characters from the original comic book series have been confirmed to make appearances in-game, including Hershel Greene and Glenn Rhee. Players will be able to meet them before the plot in the comic book begins to take place.
The time span from one episode to the next gets shorter and shorter as the season goes on. Episode 2 takes place three months after Episode 1. Episode 3 takes place one week after Episode 2. Episode 4 takes place 12 hours after Episode 3. Episode 5 starts exactly where Episode 4 left off.
The trivia items below may give away important plot points.
According to unused audio clips found in the game files, Lee was originally going to return to the farm himself to inform the group about what the dairy had to offer. They also featured a dream sequence of Doug/Carley questioning Lee on why he didn't save him/her, and that he wouldn't be able to save anyone.