Sheyenne Oaks looks like a very pleasant relaxing campground but no, haven't stayed at that one. We wouldn't hesitate staying there if we needed to be in the area....good place for your family to visit. I assume you'll see some horses there in the pasture...nice.
It doesn't appear to be a city park though.
If your family is nearby you could have them check it out for you and perhaps pick out a good site. You could also have them ask around for suggestions. There's also Fort Ransom State Park just west of Sheldon and 46/1. Never stayed there though. It gets high marks on RVParkReviews.com
Fort Ranson State ParkFort Ransom State Parkhttp://www.sheyenneoaks.com/Also, Sandager City Park, Lisbon. It has a pool though so might be crowded and noisy. We'd stay at the state park.
http://www.rvparkreviews.com/regions/north-dakota/lisbon/sandager-park-pool-campgroundWe have also stayed at many city/county parks and never had a bad experience. Good luck!