What extras should I insist on in a new Class C

We spend the winter in central Florida. Our furnace uses up the propane too fast to keep the tank full. A cube heater is always it the way and does not heat all that well. So I installed a toe kick heater with a remote programable thermostat. It's in the wall space under the refrigerator. It's rather quite, and works and heats like a regulator forced air furnace.
We are on a meter and pay for our electricity to the electric unity.

Dusty