I think these size wars are beyond silly.
Years ago I had a young Rottie. She was attacked once by a mini Doxie. Thankfully by that point I'd gotten her reasonably well trained (not perfect by a long shot), and she just looked at me while the Doxie was hanging off her neck. It was kind of funny in hindsight, as he was of course never a serious threat to her. She outweighed him by about 70 pounds. Her head was almost as big as his entire body.
Now I have a Shih Tzu. He's been rushed (not attacked, thank goodness) by several pitbulls, an ACD, a GSD and a couple of hounds. Those are just the ones I can remember off the top of my head. It's an all-too-common occurrence in campgrounds. In the heat of the moment and in hindsight these are most definitely not funny. They're very scary, as the larger dogs could quickly and easily kill him. Thankfully the Tzu is unflappable and quietly and calmly stands his ground and gives them a "What is your problem, stupid" look. I'd like to take credit in the training department (like all of our dogs, he's been trained extensively), but it's mostly just his nature. I really should have done therapy work with him.
I do not think all little dogs are untrained yappers (which is silly) nor do I think all bigger dogs are uncontrollably aggressive (which is also silly).
All of our reports here are anecdotal, and for most they're colored by the person's usually very obvious bias, and certainly by the size of the dog the poster currently owns. It gets tedious. Humans are silly and nonsensical most of the time.
OP, you will encounter some RV parks that don't allow your dogs. But I don't think there are so many of them that it will present a huge problem. In our experience most people in RV parks are dog friendly and don't have the biases that are often displayed on here. Over the years we have RV'd with well trained dogs of all sizes and have never met anyone who seemed put off by any of them. Good luck!