I'm still getting familiar with the new scripting. I never did get this working properly in Oblivion either.

I need code that will trigger a quest stage after 24 hours of game time, regardless if the player stays in the same cell or not (this was my issue in Oblivion and only sometimes).

Any help is appreciated.

That's no problem in Skyrim, take a look at http://www.creationkit.com/RegisterForSingleUpdateGameTime_-_Form.