If you have a turbo controller like a Hori it can help immensely for this achievement. Here's what I did:
- Pick a position player. I picked Carlos Ruiz of the Phillies so I could get the achievement for winning the World Series in My Bobble mode as well.
- Set the hitting/batting function to "Auto" in the settings, and the computer does the hitting for you.
- Set the controller to turbo the "A" button, and it will advance through the season, automatically starting a new game as the previous one finishes.
The downside of this is that you still have to keep an eye on the game because if someone from either team gets a walkoff hit or home run, a postgame highlights package will loop (you need to hit B to stop it, so your A turbo is ineffective). Even with that downside, this method will allow you to do something else like watch a movie or read while only occasionally glancing at the game.
Is there a way to turn the postgame highlights off? If so, it would allow people to leave the game on overnight.