Board Thread:General Discussion/@comment-5821891-20160307122113/@comment-24674051-20160308183128

I would need to go back and review the episodes in question. But it sticks in my mind that when Cora showed up in "Mother", Regina was like "How did you get here?" That would seem to imply that Regina did not think her Mom could get back. That was not the case in SotD. Which would lead me to believe that SotD was likely Cora's first trip back, and Mother was the follow up. Which also lends more credibility that Regina was concerned about Cora just "showing up" as she was casting the curse, hence the quest to send Hook to kill Cora.

So, it would appear that the order of events is Heart of the Matter (Wonderland), SotD, Hat Trick, Mother, QoH. And the last 4 happen is fairly rapid succession (probably a matter of weeks).

That's my opinion anyway.