You could also use an air compressor to blow out all the lines. First you drain the fresh water tank and water heater. Close those valves, hook your compressor to the city water connection set at 40 psi. Open all faucets one at a time until no water comes out. Don't forget the toilet and outside shower. Once that's done, open all faucets and let compressor run for about 10 minutes. Disconnect compressor and reopen fresh water drain valve and water heater relief valve, pour antifreeze in all sinks, shower and put about an inch in the toilet. You're set for the winter and don't have to flush water system next spring. Been doing this for 15 years with no problems.
2000 Itasca Suncruiser 35U
2002 Jeep Wrangler Sport, 2005 Jeep Liberty Sport