just an update on my recirculating water mod to prevent freezing:
We camped last weekend with two nights into mid 20s F. (Cimarron Canyon NM) I thought that would be a good test so i activated the power to the system and went to bed. I didn't hear the valves open all night or hear the water heater running so i thought that something must not be working correctly. so i got up in the middle of the night and ran some water and it was all ok. so back to bed.
Next morning i checked the system and all functioning as intended. Apparently the mid 20s was not cold enough to get the fresh water line to 34 deg F. I have an insulated tank and water line. So, i will need some sustained cold weather to get a real test.