Starting with empty tanks....
I'd just drain the low point drains, drain the water tank, blow out the lines, replace the low point drains, blow out each faucets one at a time, reopen the low point drains, blow out the lines one more time, siphon the remaining water out of the water heater, add antifreeze to the traps and pour about a gallon of antifreeze into the black tank.
Done...takes 15 minutes taking your time.
I don't put antifreeze in my lines...never have...never had any problems with lines freezing...ever... Lines can't freeze if there is no water in them. The few droplets that are left are not enough to cause problems.
De-winterizing the RV for me consists of hooking up the water
Thanks!
Jeremiah