Ya IMO you cannot leave your property with children still in your house even if they are 'sleeping'.
IMO that is a liability suit waiting to happen as technically you are off your property if you are crossing the street to go and get her and well anything can happen in those few minutes and what if the bus is late and so forth
Is it possible to have an older child walk her from your house to the bus stop and back again or to ask another parent who might be getting their own child anyway? This is what many of my friends do and they pay the person $5.00 a day for the return trip morning and afternoon?