- Resting in dungeons
It's impossible to rest in the Zhentarim hide-out, suggesting that they are experimenting with allowed areas for resting.
- Rests before worm take-over
The current build has no limit to the number of rests before the worm takes over, but the story suggests that excessive resting could result in a game loss.
The Zhent hideout should be an ideal place to camp. If you're their "friend" or wiped them all out and it's empty.