Another thing, do dungeons / npcs respawn using game time or RL time?
Game time.
Things like merchant inventories and dungeons all have different amounts of time before they respawn, however. Unlike Oblivion, where everything reset if you hadn't visited in the past three days, it's now a much larger time frame, and can be anywhere from three days to thirty days.
This can cause problems with low timescales, because it means that the game is storing data on every location you have visited in the last month, which can lead to save bloating (which lead to corruption in Oblivion).
Hopefully, the SDK will let us have some sort of control over the respawn rates of different areas, however, so that people who prefer a 1:1 or 1:5 timescale won't have to wait for a month to revisit other locations.