Check the circuit breaker that the outlet is connected to. Is it a 20amp or a 15amp? Is there anything else connected to that breaker? Other outlets, appliances, etc.
I agree with above to use a quality 30 amp extension cord with a 30-15amp dogbone adapter at the outlet end. If nothing else is connected to the breaker and she is ONLY using the AC (no other appliances in the RV), or just the microwave or just the coffee maker, then she should be OK. If she wants to use two or more at the same time, then she will need to install a dedicated 30amp breaker and pedestal and hook into that.