Hart Ranch seems to be pretty central to Badlands and Wind Cave and has lots of amenities if that's your thing. We are an old couple with no children with us and much prefer Custer State Park, Gamelodge Campground.
We were disappointed with Voyageurs since we don't have a boat or fishing equipment with us when we travel. We did take the park boat on the park lake tour and enjoyed it. When we visited there it was part of staying a couple of weeks in Gilbert, MN at
Sherwood Forest Campground which is a city park and has very basic facilities but you can swim just downhill from the campground at Lake Ore-be-gone which has a nice beach area. It's about an hour and a half from Voyageurs so you may find somewhere closer and more convenient.
