"This appears not to be the ideal solution for the person in question who still wants access."
She sounds rather pushy and it sounds like she wants to decorate the place somehow. Which isn't okay, of course, as you want the place presented as you present it, not after someone else has walked through, possibly tracking dirt over the floors, dropping bits of things around, not to mention maybe having to use the bathroom while there and leaving water slopped around the sink and drying their hands on clean, fresh towels, etc. all of which you would be blamed for.
I would impress on her that what you rent is accommodation, not an event venue. I would also be really clear about no unregistered guests. I can see Mom assuming that she and others can come by and hang out.
@Laura2592