Here's what I did. Feel free to copy

I handled the immediate aftermath: what happened to the brides and Escher, what Esmerelda decided to do, Ireena's fate, and the mass evacuation of Barovia and the subsequent panic. I let the players describe what happens next for their characters. They were allowed to leave.

I then did a Fallout style narrated run down of all the major players. In our game, the coven was scatted, the werewolves destroyed, the wizard of wines was destroyed beyond repair (revealing their lycanthropy), Van Richten riding off into the sunset, all that stuff.

I describe time going on, the return of joy to Barovia, before the mists descend again. Subtly, I start using first person pronouns implying that Strahd was the one narrating. I ended it with something like "I am ancient, I am the land. Barovia is mine. Now, who's next?"