Oooh, I actually like that! Talking to Arathorn could come across as creepy/crazy, but if we are making her this very 'practical no-nonsense' type of person, that would be one concession to sentiment that might humanize her. Obviously, we would have to be really careful how we did that, but just looking up at the sky and making comments about this boy that he left her (either in exasperation or a I-wish-you-were-here-to-see-this type of way.....)....well, that could work, maybe. But of course - used sparingly.
If the devoted servants are ARATHORN's people (rather than her mother), that could still serve to keep her isolated. I think we can add to her household without destroying the visual isolation we are creating for her. But...we'd have to be very careful how we did it, is all. There's a lot of pitfalls to avoid.