I take it your not in an RV Park. Otherwise, you could use an extension cord from the electric pedestal or your unit to run a heater in the enclosed space.
We are in NE Indiana and so far it's a balmy 35 degrees. We're stuck here until Feb.
Usually, DH will bring 100# tanks from his project that they rent to keep the inside of the store warm. Last Winter, the RVP in KS rented us 100# tanks for the cost of propane only. But DH had to haul the tanks himself and he didn't want to do that again. So we ordered a larger LP tank and had it hooked up. Propane Co will refill as it gets low when we call.