Mice. Rats will chew their way through even thin metals. Certainly plugging up holes with foam from Lowes etc that rats and mice don't like at all. Mice can get in a hole about as small as a pencil, and if need be enlarging it.
Most effective way is an animal. Ferrets, cats. Ferrets like to make nest of fabric and so on too though.
In enclosed storage they make a lot of sense, outside, of the rv but you do have to take care of them to an extent, like even barn cats.
The cat is perhaps the better choice in most weather.
A rat snake or other type will work but most people are not in tune with them.
Farmers know, and won't harm the snakes in the barn except the poisonous ones.
Baited Traps might get most or even all but not necessarily.
I have two of the plug in whatchamacallits, in our huge basement at home. So far no rats but one snake did crawl in while I was doing some cleaning with door open.
Poisons work well but we don't want them in the walls when they die.
Those with Warfrin do not harm humans and most others. The mice and rats go looking for water. So have some water, nearby, but not in the rv. Warfrin is a blood thinner, prescribed for humans.