Certain quests will feature what Bethesda is calling "Radiant Story" where the game will send you off to a dungeon that you have not yet been to to perform some task. So a quest with one character may not be the same as the quest with another character.
Edit: I think it may even be dependent on things like your skills, level, play style, etc.
Edit: I think it may even be dependent on things like your skills, level, play style, etc.
This is going to be hard to pull off. What if you have been to every location? What about dungeon loot?