Looking for a new overnight spot

DH and I are taking a trail riding trip to our favorite ranch in the Black Hills, SD this summer. We took our first trip there about 25 years ago, and when we took 2 days to travel from central IL, we stayed at Yankton, SD and another place--forget the name, in Nebraska. Usually we drive I-74 to I-80, then I-29 to I-90, to the Black Hills.
Does anybody have any recommendations for a new place to stay overnight? I'll be trailering 3 horses, and I ALWAYS have a negative Coggins and health papers. We also have had brand inspections on all three done for registration.
Don't mind going off of the route, just want to do the trip in 2 days. After years and years of vacations and National CW Events where we would drive all night, I just don't want to do that anymore. ANY suggestions are welcome. =D

There is a place in Mitchel SD with covered runs and electric camping.

Please send me a link to a web page. Change in plans--DH and I decided that we will take the year to prep the trailer and truck for our next trail riding trip, and go in 2014. Instead, we're going to take a trip west and look for new camping locations, so I'm going to for this thread. I am looking for places close to I-80 across IA, I-90 across SD and Black Hills locations, and I-70 from CO back to IL.

If you're traveling I 70, Kanopolis state park is a good place to camp and ride. It's not too far off the path, just south of I 70 on I 35
Rockin' K Horse Campground / Horsethief / Areas / Kanopolis / Locations / State Parks / KDWPT - KDWPT

Thanks!