They are under the rearmost dinette seat. The water filter is under the bed beside the water pump. I did not winterize last year, as I head south. I noted that although not required by Girard to plumb a water heater bypass for the small amount of water in the tankless heater, Thor plumbed it. Also worthy to note there is an internal thermostat for the water heater which activates just above freezing point, thus if you winterize you should turn the 12 volt power off at the heater.
2018 Four Winds 31Y