Do I need two propane tanks

If you plan on doing a lot of sub freezing weather camping, then some sort of dual tank setup is probably a convenience well worth the investment. For now I just keep a spare tank inside a milk crate in the pod when towing, then leave it outside next to the tongue. It takes me no more than 5 minutes to swap out a tank in the dark under the front light on the pod. Even if I couldn't find my glasses and wasn't able to thread the strap, it would be fine until morning with the clamp holding it in place.

I tank for us and 1 group 31 battery. The 2 tank mounting would always rattle loose on wash board fire roads.

 I run with 2 6 Volt batteries and  2 30# propane tanks on my 179.  I like the manual throw over reg over the auto.  I then know that one tank is dry and needs to refilled.

The bulk of our camping is in the fall, followed by spring and lastly summer.  Per year we go through 1.5 tanks of propane, the majority of it being used for the furnace, followed by fridge, and then cooking.  Our batteries 12v  marine batteries will last us 3-4 days each during cold weather camping, so we can expect 6 - 8 days out of both batteries, and they are now beginning their 6th year.

that's a great idea, let ,me see if I can change it. thanks again