Ayuh,.... Just Drain everything, 'n forget about the antifreeze,....

Air, just don't freeze,....

I don't recommend RV anti-freeze anymore as it jells up in the block and blocks the steam holes in your head gaskets. I just tore my motor down this last spring because I heard a knock, it ended up being my drive which I discovered after it blew. But I digress, when I pulled the head off I noticed pink and blue goo plugging the steam holes in the head gasket. Now I drain the block and headers, I pull the sea pump off to check the impeller and store the impeller until spring so it doesn't take a set. I then pour a cup of automotive anti freeze into the thermostat and 1 in the main line coming into the engine to back wash the oil cooler. I then use a remote starter to crank the engine while spraying Amsoil engine fogger. By not running it while fogging, I don't foul out the plugs and I get multiple seasons out of them. I have done a tear down on a motor done this way and the cylinders are perfectly coated with oil which also makes it easier on startup in the spring. The best part is I can do this in the garage and it takes way less time and money.

When you drain the block how do you know that all the water drains out ? Can anyone tell me if any water stay above the thermostat when you drain the block from both sides? I understand there will be water left in the headers