Any tips for the Royal exclusive Palace?

I'm gonna be doing Maruki's palace soon. I'm thinking off starting the infiltration on the palace as late as possible before the deadline. Are there any points in the game where you have to leave the palace?

I'm not talking about the intro to the palace of course, I'm talking about when you start having the ability to choose when you can enter the palace or just do something in your freetime in the resl world. I've already rescued Sumire from Maruki, that's where I'm up too.