It depends somewhat on what amp rating you have on the receptacle that you are plugging into in your house. I have done this many times but I am careful about overloading the circuit. If I'm only interested in running the fridge and few lights then usually a 20-30 amp breaker outlet works fine for me. If you're worried about overloading a circuit can you use the propane to run the fridge?
My slideout on my fiver only runs off of the battery system. No batteries means no slideouts for me.