We have a Class B now, so the dog comes everywhere with us. If we go in a restaurant, store, historic site or wherever that he can't come he stays in the RV. It's his home away from home, so it's exactly what he's used to. The only difference is that in the RV we crate him. He's not crated at home, but in the RV we do it for his safety and to keep him from damaging anything. We pull the shades and leave the AC or the fan on for white noise. We have an on board genny, so we can run it when he needs the AC.
When we had our Class A, a toad and two dogs they stayed in the RV when we went out and they couldn't come. Again--crates, leave something on for white noise, etc.
You want to make sure barking while you're gone isn't an issue. Some will say that's impossible to know but in reality it's very easy--ask neighbors (you can ask them to listen for barking before you leave and even give them your cell # and ask them to call if there's a problem) or set up a camera or a voice activated recorder. For the first few times it would be good to leave for just a few minutes, then gradually lengthen the time you're away. If necessary practice leaving the dog in your trailer while you're at home to get her used to it and see how she does. It also helps to make sure your dog is well-exercised and tired before you leave, and to leave her with a safe, yummy chew toy.
Of course the above assumes you have reliable electricity and can run the AC to keep your RV at a safe temperature for the dog.
Many campgrounds state that dogs are not to be left unattended. Some people take that to mean they aren't to be left outside an RV unattended, others take it to mean they aren't to be left even inside their own RV. We had our Class A for ten years and I always asked. Every place we stayed or thought about staying I asked in advance. In those ten years in only one instance was I told that it was not okay to leave a quiet, well behaved dog inside our RV. Of course we chose not to stay there. My conclusion is (obviously) that if this ambiguous rule has ever meant that dogs couldn't be left alone inside an RV it was meant to be selectively applied in retrospect for troublesome barkers. But--ask. We've encountered a very, very small number of campgrounds that state unambiguously in their rules that dogs can't be left unattended, ever, even inside their own unit. So we just avoid those. They have been very few, so it hasn't been hard.