not sure about that specific model, but on the 3 Jaycos ive owned there is always a tube hanging down under the camper called the LOW POINT DRAIN. Thats a good place to drain the water out, I use a fitting that screws into the fresh water supply fitting and uses a tire chuck to blow air thru the lines with all the inside valves open.
This is after draining the hot water heater and put the water heater in bypass.
Once they are all blown out you can run the winterizer thru the pump system into the lines. Thats how I do it anyway, but I may be doing it all wrong..