Couple of unsolicited dungeon-splaining tips:

• Whenever I want AI to generate randomness I ask "for as true random as you are capable of". Might not be necessary in this context but remember some models are so eager to please they can write a pleasing narrative even when you want randomness (I saw this when asking for chatgpt to give tarot readings - once actually random it was a lot more fun)

• Get the AI to take its own notes, especially if you are using a tool rather than a chat window (actual documents, preferably markdown format, are best). This helps avoid errors or mis-matches.

• It might also be a good idea for it to plan out the beats and just not show you them until they are ready to be revealed. Especially good for longer campaigns. Another way you can avoid it going off track because then it is working from a plan that could even be shared with another model or session.