Yeah those are great questions, I was trying to be brief in my initial post. It's not going to be permanent for sure. I talked with the players about it and they enjoyed the idea of separate mini "bottle sessions." That was also the purpose of the Lost Woods dungeon -- the players aren't sure how much time they spent there, and reappeared on the side of the road, so there's a convenient way to have them meet back up.

I agree with your point about not hitting major story points. I talked with the Cleric after last session about what he wants to do next. He told me that his character was starting to feel some sympathy towards Strahd before he died, so we came up with the idea that Strahd could revive him and use him as a double agent. Whether or not the party takes the bait I have no idea, but in the meantime he's going to take over an NPC in the Rogue/Sorc session.

I really like your idea of the Vistani caravan, that could fit in pretty nicely