Mr. Buddy as a main heater, yet considering a heat pump or heat strip??? That leaves a lot of doors open LOL! If you have electric, why wouldn't you go with an electric heating solution and thus wish to deplete the propane which I assume is in your mind or you would not be asking about the viability of electric heat methods as well. If the campsite includes electric, I'd consider going with a few electric ceramic heaters (just because I can't stand the continuous noise of an AC unit).
Otherwise regarding a non-vented gas heater, I had my first and last season with a non-vented gas heater (aka xxx Buddy) as that will leave the inside of your coach and especially under every table or under bed or any kind of storage bin, and all of them seeping wet with moisture from that gas heater. Run it all season and you'll have mildew everywhere. Additionally if you have any expensive camera equipment, or other moisture sensitive valuables stowed, you'll pull them out find those things ruined from the water. (Propane plus oxygen yields heat, carbon dioxide and water)
Otherwise if you were at a place where electric is available (supposedly assuming it's included in your campsite fee) why would you even consider the hassle of bringing in a portable propane heater (with the constant need for refills)?
I'll tell you what I did one winter where I stayed in a single location in near freezing temperatures the entire winter. The electric there was not large enough to run a heat pump but historically even when power is available I always consider the heat pump my own last resort due to the noise it makes. I had a full 3' x 3' wall electric ceramic heater that works well in the 40-50F range and this normally keeps me comfortable but at near freezing it would keep only part of the 24' coach warm enough. I ended up after getting sick of wearing a coat for months on end, using my "extend a stay" and just renting a 50 lb propane bottle and running my furnace off that all winter - minimal noise and while a hassle adding the propane bottle, it was only once and ended up making me the most comfortable considering all the other options I tried.
Even when I had the non-vented propane wall heater blasting and before I discovered the coach was being drenched in water, I got really tired of having to worry that my carbon monoxide detector might fail, as well as monitoring the new carbon dioxide meter I installed (the real killer when you use an non-vented and one without a low-O2 shutoff feature). You see, a perfectly working heater will never set off a C0 meter and you can wake up dead as a door nail and it will never indicate there is a problem because the normally operating heater eats oxygen and turns it into carbon dioxide (CO2 and NOT CO) and water and once your drawers and stowed items get saturated with water vapor and thus your atmosphere gets saturated with both water and carbon dioxide. In the case of C02 replacing the oxygen, there is nothing that will keep you alive if you have any ventilation restriction - and this includes when you inevitably have a window cracked 1/4" in a 30MPH windstorm, fall asleep and wake up to "dead calm" and with something else perhaps dead at the same time, something that you won't like losing - trust me.