I pulled the slide in and squeezed past the dinette table after killing power. On my 811, the main cutoff was under the sink - I thought Arctic Fox moved it to be accessible through an exterior storage compartment?
If you add solar to your camper, the panel will take care of parasitic losses through the radio and detectors and you will not have to use the disconnect. This assumes you do not use a cover or store it in a dark location.
My hot water heater did not have an anode or sacrificial rod. I would flush the tank once a year but did not worry if a little water was left in the bottom of the water heater when winterizing.
My steps for winterizing when you do not have power for a heater:
1. Open low point drains for cold, hot and fresh lines
2. Open all faucets
3. Attach air line to city water hookup
4. Run compressor at 40-50 PSI
5. Close off low point drains and faucets to pressurize system
6. Cycle different faucets and drains on and off until no more water comes out
7. Leave low point drains and faucets open
8. Pour RV antifreeze into each drain trap
Don't forget your exterior shower connection requires the hose connected to properly drain. I also make sure I clear the the toilet valve of water so it does not freeze.
We camp twice a month year round, so this becomes easier each time you run through the steps.