This really beats replaying through two entire games. Dragon Age Keep lets you relive Dragon Age: Origins and Dragon Age 2 in preparation for Dragon Age: Inquisition.
The best part about remaking all these decisions? Brian Bloom, the voice of Varric, will recount all your major choices in a neat looking motion comic thing.
Dragon Age: Inquisition comes out November 18th on PC, Xbox One, Xbox 360, PS3 and PS4. Head over to dragonagekeep.com in order to set your world state.