Everybody beat me to it, but +1 on the RV antifreeze in the drains. Don't forget the toilet tank.
Shut off the water and blow out the supply lines. Work from the fixture the farthest away from the supply. Drain the water heater and tank if you have one, keep those open as you blow the system out. Then you will have done all you can.
Dave in WI
"Daddy, it's five o'clock sometime!"