Hey just a suggestion if it suits your living situation in the RV or how handy you are with DIY projects, but for this $ amount you could get a portable gas powered shower and a gas powered yacht heater, and a tractor supply petrol generator, and at least a couple of 12 volt batteries to power lights and recharge phones etc when your generator is off (or add a couple of small solar panels, but that's another big upfront cost). You don't need to run the power all day and all night - just morning and evening are OK for the fridge. The yacht heater (eg dickinson) will heat a whole RV safely. Your total winter energy cost could be down to around $100-200 month depending on how much you're at home.