[DutchmenSport]

gm1216, I have the 375FL model which is the fore-runner 377FL (no loft in mine, otherwise, same floor plan with slightly larger bathroom because there are no steps going to the loft.

When temps reach that low (actually 15 degrees or lower), my Montana will burn through 1 thirty pound tank of propane in about 24-30 hours when set to around 60 degrees. If you are planning on running the furnace, you may just run out of propane before you return home.

If you are going to go ahead and blow out the lines, then go ahead and pop the anode rode / drain plug on your water heater too. Just take it out and let it drain. Once its finished, insert the plug/rod. What little bit of water sits on the bottom of the tank will not hurt anything if it freezes. This way, all your water lines have some protection. Make sure you dump your tanks too.

Running electric heat inside the coach will not do anything for the water heater, holding tanks, or water lines located in the underbelly. That is what the furnace is suppose to do, keep everything under the floor from freezing.

At 7 degrees, with no heat, everything inside the trailer will be frozen solid within a few hours. I know. I set out cups of water and test how long it takes them to freeze up. When it's THAT cold, with no heat, it does not take long at all.

Personally, I'm not a fan of blowing only. I have always used the RV antifreeze pink stuff. I've done it so many times, and sometimes several times in one winter season traveling from freeze zone states to non-freeze zone states I can't even count any more. For me, it's RV antifreeze. If it be 1 hour of cold in those temps or 100 days.