Hey, glad you're enjoying the game!
As for free-roaming around the castle, there are no plans to change how that works; it will still take place between episodes (but not during them). This section includes quite a bit of unique dialogue and bonus scenes that would be a shame to miss out on. However, if this part of the game isn't for you, there will always be clear instructions on how to move on to the next episode's story (whether via the quest log or quest icons on the castle rooms).
Regarding the next episode, I’m currently 10% of the way through, and you can track that progress in the announcements channel on my Discord.