I looked at the web site for Allentown KOA and it looks like almost every KOA. It is basically a parking lot with trees, a pool, laundry and store.
We just completed a month long trip through thee Rockies. Even the National Parks have sites pretty close together because they need to get as many people as possible in the campgrounds to try to meet demand. The only way to get a huge private site is to try true boondocking. We stayed at a National Grassland and were the only campers for 10 miles (we think.)