I recently bought the ultimate edition of Dragon Age: Origins, which includes the Awakening expansion pack and all the DLC. It looks like the DLC is modular and isn't integrated into the game; do I need to play them separately? How do I access them?
The following DLC are integrated into the main game, and you can access them any time after you gain access to the region map:
The following are more-or-less item packs, and you should have access to them by the time you gain access to your party's camp:
The following are separate stories requiring you to select them as you start a new game:
Note 1: Can import your character from Dragon Age: Origins, but your companions don't follow you and you can't access the main storyline or the other DLC (except for the non-Feastday items that you might've imported with your character).
They tie into the main game. When you view your map, the DLC will unlock a few places that you can visit at anytime.
The DLC should be shown as a place you can visit with a Golden tint: Such as the The Stone Prisoner, etc.
To clarify, the DLC can be played side by side with the original Dragon Age: Origins. The Awakening expansion pack must be played separately as those events take place after origins.