Also, don't forget the outside shower, so often people overlook this and end up cracking the valve.

I just returned from storing our RPod for the winter. Perfect timing since as I drove away from storage I encountered a major snowfall and slush covered roads.  Yes, winter is coming! :-(

You're probably fine with out it where you are but NO, you do NOT want to use auto antifreeze.  What you want is clearly labeled RV antifreeze.  It usually $3 a gallon, plus or minus.  You don't want to drink it but you won't die if there's some residue left in the pipes after you flush it out of the system in the spring.

TT

I'm pretty sure you are not talking pet friendly auto anti-freeze.  We are having a cold snap now. Getting to low 40's at night. I think I am safe without it. 

The protocol for antifreeze is to first get as much water out of the sytem as possible.  Pump off, open all valves, remove the caps from the low point drains and the fresh water tank.  Let the water run out.  (The method is different for blowing air out under pressure.)  With all pressure relieved from the system, remove the anode from the water heater, let it drain.  Put the WH bypass valves in the winter bypass positions.  Don't guess.  Different Pods have different bypass methods.  For most older Pods the outer valves are closed and the middle valve is open.

With all water out of the system, close all valves and cap the low point drains.  Put the antifreeze suction hose in a jug of antifreeze, open the valve on the suction hose, turn on the pump.  Now it's handy to have a helper.  As the antifreeze is sucked up, opne one valve at a time until pink starts coming out.  Sink hot, sink cold, shower hot... outside shower, toilet.  It might take more than one jug of antifreeze.  Turn off pump, close the suction hose valve.  Poor a little antifreeze in the toilet and leave it.  Pour about a cup in the shower and sink(s) traps.

Some people do nothing more than blow out all of the lines.  The bottom line is, however you do it, all water must be out of the lines and valves.  Either way, antifreeze in the toilet and traps is important.

TT

Make sure you know how to turn the valves on the water heater.  In case you don't know, you do not want antifreeze in the water heater or the fresh water tank.  There are plenty of people who can help if you have any questions.

TT

Charlie, your line of thinking is why I suggested bypassing the water heater.  With  the WH bypassed there's no air getting past the bypass valves and out the anode opening.  No need to blow out the WH with the anode removed.  And with the WH bypassed all of the hot (and cold) pipes can be blown out.  I don't see why you say the WH valves need to be in their normal (meaning summer) positions to blow out the hot water lines.

TT

The water heater should be in bypass mode.  It's a good idea to put the anode back in, maybe just loosely, to keep critters out.

TT