Good Sam used to list Enclosed dog runs under Additional Amenities but they no longer do it. Why? That is a very useful feature for those of us who travel with dogs.
I know that many people probably use them, however in 6 yrs full-time we have yet to see a dog in any of the campground enclosed areas. As for ours, we have tried a couple of times, but she just sits next to us. She is used to walking with us outside of any enclosure.