For me, I don't travel in my RV with my pets with the expectation of leaving them in the RV while I see the sights. My RV style is to go places where the dogs can be out and about and enjoying the outdoors right along with me. This means I haven't had to worry about the temps inside the RV when I'm not there, because if I'm out, the dogs are out.
Now, I have the parrot camping with us also. Because he stays in the RV at all times (in his travel cage), I have to be more careful about the weather and the RV temps. Birds are extremely sensitive to fumes, etc., so running a generator while I'm not around to ensure his safety is not doable.