Hi...
Yes, white switch is the electric water heater. Will only operate on shore power or generator. I leave my switch on all the time unless I am storing the coach.
The refrigerator is a standard household fridge. It is connected through the inverter system and this will run on shore power, generator, or battery (inverter). It draws about 11 amps, based on how you use the coach, you may not last to long on just the batteries and thus will need to run the generator once in awhile of you are dry camped.
Thanks for the remark on the site. Now check out the cruise we are putting together.