If you ever have to replace the alternator you could just up size the alt. to say a 160 amp, should be enough for x number of batteries. There are sites on line that can break down the numbers if you're interested. The one skool bus that I have seen up close had a 140 amp alternator on it.
If you put in a bank of batteries and a good inverter you can run just about anything short of the AC for a period of time, TV's, fridge, cell charger, computer's etc will be fine.
It's the bigger items with a heavy current draw that kills the batteries quick.
Do your research before you do anything....
edited for spelling. dumb computer of mine