To the OP,
I did it both ways. First time, 1500 watt whole house w/ transfer switch. It worked good, but too many things to remember, AC, water heater, Fridge, etc etc.
In my new (to me) MH, I went w/ a 400 watt inverter, powers only the stuff I need, tv, dvd, vcr and sat receiver.
Much simpler, and fool proof.
If I need the big stuff, I fire up the Onan,
For battery charging, I unplug my converter from the ac system, and plug it into my Honda 1000. When I'm camping, my converter only stays plugged into my Honda 1000