Phd Student here: Where is the line between free labor abuse vs....whatever the "good" version of free labor is?
I am very sympathetic to your supervisor, so my discussion here will be biased. Good supervisors are not given much recognition nor appreciated much by the system. The system seems to reward poor supervisors by giving them time to do more research. 

Could this be a quid-pro-quo situation? It is clear that menial tasks are out of line, and there is a line between exploitation and also asking for assistance. Especially, so she can spend more time to do more for you and her students, providing responsive feedback etc. So the issue is whether you feel appreciated enough right now? And how much time you are spending for her and her agendas. How much of her agenda lines up with your future goals and aspirations? Try to align your agenda and activities so you are not feeling exploited but part of her team. 

Despite all this, if your agenda is not aligning, then speak up and try to set boundaries. Realise that your time and access may deteriorate to the bare minimum that other supervisors seem to give? May not necessarily be as retaliation but rather as the result of her time being reduced as well for "menial tasks". Some people really struggle with "menial tasks" and changing focus can be a struggle for those people who prefer conceptual and more abstract work.