First a few words that don't directly answer your question: For better or worse, there don't seem to be many "conventional mother/daughter relationships" once you look and listen more closely.
And rest assured that your solution doesn't sound harsh"”only realistic and pragmatic and quite surely based on a lifetime of dealing with the people and situations involved.
If your mother's move is imminent and certain, your best solution is to secure a power of attorney in Montana"”the state in which she will reside, since her accounts will technically be located there. You can get a copy of the power of attorney form by searching "Montana Code Annotated" and "72-31-201." While the document is fairly straightforward, you could consult a lawyer with any specific questions you have about it.
While performing your duties as your mother's agent in another state, there are helpful steps you can take, such as getting online access to her bank accounts. In many situations, this is about all that is required to handling the simple finances connected to billing and paying.
It also sounds as if you've done some research about your mother's new community and the resources there. Should you need additional help, such as securing a volunteer to carry out social visits to your mother"”particularly as she settles into her new community"”those resources can likely offer some direction to you.