Run water pump while doing the rest of this (water pump will do the same job as a compressor and the ShurFlos are designed to run dry for a while, which clears the pump itself).
Dump/drain fresh water tank and open all low point drains and exit points, and open every faucet and exit point (include low point drains), flush toilet and block pedal to keep it open, remove water filter cartridge (if applicable), drain water heater or follow winterizing instructions if on demand type.
When all visible water and dripping has stopped, dump holding tanks, b/g, leave everything open until you get home, and you should be fine.
We've done it a few times.
2018 (2017 Sprinter Cab Chassis) Navion24V + 2016 Wrangler JKU (sold @ ????) - 2016 Sunstar 26HE (sold @ 4600 miles) - 2002 Roadtrek C190P (sold @ 315,000kms)