FWIW - If you turn the master switch in my coach off, nothing works except the inverter, fridge (if inverter is on), microwave, and the light over the dining table. If I turn the inverter off, nothing would then work powered by 120V and all the 12VDC stuff is dead as well. It won’t start either, although I have not tried to start it with the switch off. I know it won't run, because, when I changed the alternator, I put it back the way the OEM one was wired, and the engine would not shut off with the key. Once I turned the MS off, the engine quit, and the genset won’t start either I don't think. See my post about the alternator change to read what wire was wrong.
I have the residential refer, and if the inverter is not on, no ac, no gen, but MS on, it won't work either, as it needs 120V.
RV refers need at least 10.5 VDC so the control board has the necessary power for the fridge "eyebrow" board which actually allows you to turn it off and on, set the cooling level, etc. It would be assumed, this is a switched circuit, but it appears not to be.
My suggestion is to purchase a battery disconnect switch (actually installs on the battery post) which then would kill the power to everything. As some have possibly suggested, removing the fuse would do the same thing, but then you might forget to put it back in. The battery disconnect would be a better solution. Keep in mind the arching potential when you install the BD switch, and make sure it won’t rub on anything when in the off mode so a potential fire hazard is not created.
FWIW#2 - However, it should be noted, that if you store the coach during the winter or summer that once a month, everything should be exercised for a couple of hours. If reading your manual for the genset, it says to run the GS for two hours a month at half load. The furnace manual, water heater, and all of them say some exercise of the components is necessary. This would include at least once cycle of the levelers and slides as well. This would be regardless of if they are hydraulic or electric.
Monty & Janet - 2007 Alpine APEX 40 MDTS
S/N - 75715 - Retired - Master Certified RV Tech