Antifreeze or compressed air?
Blowing the lines out with air uses no chemicals, but small amounts of water can stay in low spots, valves and the pump. Pumping RV antifreeze through every line is more certain. Many owners do both: blow out first, then pump antifreeze, which also uses less of it.
The step people skip
The water heater bypass. Without it, the antifreeze fills the water heater tank first, so you need several extra gallons and the lines further down may never get any. Make sure the bypass valves are set before you start the pump.
This is a general checklist. Systems differ – follow your RV and appliance manuals where they give different instructions, especially for tankless water heaters, washers and ice makers.