Just a comment on the electric only...
Sunday night (Well technically Easter Monday morning) a tornado came to visit just up the road.. Missed me (and the camnpground) but not the power line. There was no electric till late Wed Evening.
Now with my dual-fuel (Gas/Electric) I still had hot and cold runing water
With my Onan doing occasional service the batteries held so i was able to Internet via my cell phone and watch TV and cook
But the propane was a food saver.
Another thing. Propane recovery time is 15-20 minutes Electric 2x that so if you are using hot water.. Well my Atwood I can use both at the same time and if I had a 1500 watt element 15 minute recovery is not out of range... Dang near an unlimited shower (I have a 375 watt element however).