I’m in NE Nebraska not terribly far From Sioux Falls.
RevTac from Jackson NE just outside of Sioux City has a good long range that would be about a hour or so from there. Otherwise, Eastern Nebraska Precision rifle shooters on FB does a couple matches down my omaha every year, including a national level NRL match, the Bighorn. That’s about 3 hrs from Sioux Falls.
There are a couple other matches in NE, but those are a lot further
Otherwise, as said above, make friends with a farmer/rancher and set up a range. Once the crops come out in October/November, there is all kinds of land to shoot on, just gotta know somebody. Knock on doors, people out here are generally really good folks