Arctic insullation means a layer of foil bubble wrap between the frame rails. It does not extend to the outside of the coach. The steel I beams form the end of the tank spaces. They are not insulated.
The low point drains are where we froze up.
I pulled two 20 foot lenghts of pipe out of the underbelly and routed the water directly into the basement... avoiding the underbelly completely.
I also installed a tank space temperature sensor. The furnace heats the tank spaces enough to keep them ice free to about 0F.... but you have to run the furnace.... you can't use electric.
The furnace will drain your battery in about 7 hours.... 30 pounds of propane will last 2 or 3 days.
If you have a place to plug in Lowes will sell you a 100lb tank for about $80.00... one of those last about 7 days.