The question is that is she considered residing in the RV if she does not sleep in it.
You need to pose THAT and any other questions to your local police department, (local sheriff's office) if you live outside of municipal boundaries, local zoning board or office, or an attorney that you retain to advise you.
I will only add, that what you propose doing can ONLY cause problems for you that you fail to foresee or acknowledge.
If you desire a peaceful, strife free life, it is best to avoid interlopers (invited or uninvited).
Is it it an illegal dwelling if power is ran to it so the ac can run for when people and the dogs are in there.
Most sane adults KNOW the answer to that question without posing or pondering it.
In my mind if you spend all your time in a detached garage but do not sleep in it is it all of a sudden a dwelling because you spend all your time in it
You're no dummy, mate.
Your instincts are working.
I suggest you follow them, and abandon this soon to be troublesome, quarrelsome folly.
Think about this, even two men, two women, or a man and women, MADLY in love fall out 50% of the time, according to divorce statistics.
I suspect that fallout rate is often HIGHER among friends or relatives, if they live together or share certain property interests.
Truth be told, humans are territorial simians.
Pushed together, they are very often unable to tolerate each other for very long!!!