The previous owner used anti-freeze method, which took me a lot of effort (and water) to dewinterize this spring. 

I've read about the compressed air approach, and was wondering about your own experience of using it for really cold winters on a Rpod (specifically 2016 178 HRE).  

Thanks. 

First, drain the fresh water tank. Run the pump until it is dry (a few minutes won't hurt the pump). Remove the strainer bowl and dump the water and any plastic residue or other trash from the strainer. It is a good time to wash it. Then replace it.

Set your winterizing valves to bypass the water heater. Remove the anode rod and drain the water heater tank. Flush it out to get the anode rod residue out of it. You can replace the anode rod or leave it out at this point.

Set your compressor to no more than 50 psi. Start with the sink/shower valves closest to the water connection and always have at least one valve open. Don't neglect the toilet valve or the outside shower. When you are not seeing any water coming through the valves, you should be safe. Remember to remove the low point drain caps or open the valves if so equipped.

Add RV antifreeze to all traps and to the toilet bowl to protect them from freezing and to keep the toilet bowl flush valve lubricated. That should take care of it.

In the spring, don't forget to sanitize your water system before using.

I didn't know about the strainer bowl (actually had to google it to see what it is), will remember to do that. 

In terms of air compressor, do you think a portable one would work, like the one for tire pumping?

(Funny story, I had a brand new air compressor for years (>10) never found a use for it and sold it last year. )

I don't think a portable one would provide enough volume. Anything with a tank would probably be fine.