I would get her into a 28qt or 41qt Sterilite bin from walmart so you can manage the temps and humidity better.
I raise my temps so that cool end is at least 85. This seems to works great here when I notice a RI in the early stages
X2, This is good advice. Just a tub, and some heat tape or an under tank heater with a thermostat or a good temp gun and a dimmer switch. drill some holes in the sides for ventilation. the more ventilation, the drier it will be, the less ventilation, the higher the humidity. use newspaper so it's easier to keep clean and dry, and the belly heat can work directly.