When installing RV outlets my advice to people who do not know how to do it themselves is to have 50 amp put it because an electrician will usually get 50 amp right... But with 30 amp there are a whole lot of horror stories on the forums.
However in your case this is what I recommend,, MEASURE the voltage between the two flat blades with a volt meter capable of measuring at least 250 volts, TAKE CARE DANGEROUS POWER HERE if you get a reading of 120 volts give or take a bit (Or if you have previously used this outlet with an RV) buy a 50-30 amp Dogbone from Wal*Mart, Camping World, or your favorite RV store and use it..
Unless you need "Full power" at home, that should do you 30 amp will charge the batteries if they need it, cool the fridge and keep it cold and run ONE air conditioner.. If its good 30 amp once the batteries are full up you may be able to switch on hot water,, OR a vacuum sweeper. (Never both)
But I would trust a pro to install a 50 amp outlet, those they usually get right.