How would you work this regarding shared bedroom and teen moving out?

[IfyouStealMySunshine]

So my 18 year old (nearly 19) dd is soon to be moving from our family home to her dads house (short drive away).
In my house she shares with her 11 year old sister so I understand it’s not ideal and although am sad to see her go I totally appreciate the pull of her having her own space.

She said she will be taking everything with her just leaving the empty furniture as her dad is buying her all new things. great.

However when I said what does she envisage happening to her room here she said well I will still come and stay whenever and younger dd cannot have my bed. She has a double and about 2/3rds of the current room whereas 11 year old is in a high sleeper single bed.
No matter what I will keep both beds as I always want all my children to have somewhere to stay but what do I do for the best here? Let dd keep her side empty and free in case she wants to stay here after a night out (her words as our local city is closer to my house then her dads) or let my younger dd make the room her own? Help. I feel like I’m going to upset someone no matter what I do.

Leave it as it is for a while and see how it goes?

She might move back next week or she might not stay over for months.
She would probably be more open to a discussion about the room when she is settled somewhere else.

She can’t have her cake and eat it! If she’s choosing to move, then her younger sister should have the pick of the beds!

Leave things are initially and see how they go.

Let her keep the bed but the younger sister should be able to make the space more hers. After all the older one will only be crashing in the odd occasion, presumably not hanging out for days. She can’t have it both ways.

I would see how things go and reassess in January.

So she’s moving out but still wants the best bed so that she can crash there when she’s been out in the lash? That would be a great big no from me.