From Experience
-- Do not drive out in the Prairie's when wet, the SD Mud/Hard Pan/etc is very slippery and getting stuck would kill a trip and a tow truck is hours away
-- When driving out the Walmart/Cabella's in Mitchell SD is the last stop for food/supplies etc before the badlands/Interior -- good place to stock up
-- You are not allowed to drive out on Public land to shoot or set up, you must walk it. It is still legal to drive out on Private land or Indian Reservations if you have permission
-- Mount Rushmore is a great trip to make on a bad shooting day (rain/wind/etc) -- a couple of hours away -- Fed Govt does charge for parking but not for admission. Custer State Park is pretty neat -- Buffalo herd is generally easy to see -- State charges for admission but it is for vehicle
-- Bring a good pair of bino's, these should be about 8x or greater but smaller objectives since you are shooting during the day and there is plenty of light. I use 10x40 with good eye relief - first year my bino's had almost no eye relief and my eyes were sore from using them
-- Unless you are planning exploring the Badlands when you hit the Badlands entrance tell them you are not stopping and are on the way to Interior/Circle View -- They should not charge you admission. The younger Park Rangers keep trying to charge but we never paid (and never stopped)
From Dayton it is 1200 miles and 20 hours -- are you sure your 15 hours is correct to Circle View Ranch in Interior
UK