I liked LatinG's idea and decided to try one for myself.
Difficulty: All-Pro in 2005, from there on out, it's All-Madden
Minutes: 5 minutes with accelerated clock
Rosters: I'll be using the ones from EA that were posted on 9/19/05
Pre-season: I'll be simming the preseason
The only difference I have made is that you don't have to disable your sig if you don't want to. That's entirely your choice.