We’re very familiar with twin knobs. Zilpo is the backwoods cousin. A bit more remote, but we found the campground to be fantastic. It is more densely wooded than twin knobs. The sites are generally just as good, but there is more variety between primitive/hookup/cabins. The beach is not quite as big, but plenty big, and wasn’t crowded over July 4 weekend. The beach store has bare essentials. There doesn’t seem to be ranger programming. Not all the loops have showers in the bathroom buildings.