Today if the RV is not heated, it should reach 34 in a couple of hours. Warm, and it could take longer. 4 hours should be plenty of time.
Do you have a large inverter and at least 4 batteries?
I hope that you have a couple of solar panels too. If not, then I would be installing them. I do not spend each trip in a campground.
SunElec.com has some 140 watt 12 volt panels for $229 recently. They have the required aluminum frames, and because they are 12 volts, you can use a lower cost PWM controller.
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
Kangen.com Alkaline waterEscapees.com