CarrieCookie actually, post-university, I think it's wise of op to view this as a new relationship; three adults sharing a space, replacing the adult>child dynamic, and it's good to sort some ground rules out from the beginning, especially if the bf is staying over a lot.
It sounds like it might be a stretch financially and op's routine and physical space is important to her, so there are things that need talking about. I totally get that.
Op's asking because she wants to lay down some ground rules at this point so that she can do this for her DD while maintaining some of the freedoms she has gained since her DC left home. I don't see what is wrong with that at all. I think it's very sensible. And once DC have left uni, I do think it's fine to focus a bit more on your life as a couple.
And anyway, as parents and DC, we are all a mix of different personalities, some stronger than others, some more rigid or laissez-faire , some more introverted, and we all have different levels of tolerances, resources and space. There's therefore not one rule that suits all.
My DD lives at home while she attends uni and while supporting and encouraging her, I am certainly NOT doing her washing. I don't see it as a help to her to be doing jobs for her which she is totally capable of doing at her age. The way I see it, that would only make her transition to independence and the RL more difficult, not less!
She's good with money and we support her financially, with learning to drive, provide free accommodation and food, and she in turn works pt hours to cover some of her own expenses, empties the DW daily, keeps the bathroom tidy, does her own laundry (including bedding and towels) and takes her turn food shopping and cooking (except during exam period). I don't feel remotely guilty about this.
Op in your shoes, I would talk to your DD about how often your dd's bf stays over as that does change the dynamic. I think it's fine to maintain a bit of control - and space - in your home and that will lessen your anxiety about this situation. So maybe lay down a boundary such as, no bf mid-week or only on Tues and Thurs, and then you know you will have a guaranteed breathing space at various points during the week. But equally there may be times, at weekends say, when your DD would like the kitchen and living areas to be free for her and her bf. Good luck 