I lived and camped in Waterloo area for 20 years. Our favorite campground for the last few years is Big Woods Lake in Cedar Falls.
Link to Big Woods Lake web siteThis a new park with large level sites, bike trail access, and fishing/boating. They take reservations and are near the expressway, but not so close that you hear it. It is on the North side of Cedar Falls, about 15 miles from Schrock Road.
A close choice might be Hickory Hills County Park
link to Hickory Hills web site.
We camped there about 10 yrs ago. It is very near Schrock Rd. but not our favorite.
Good luck and happy camping,
Jim
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