Where are camp sites closest to the rest area, what are costs?

I really don't know, sorry. There is a campground in Chamberlain by ALs Oasis but do not know the costs

There are many places to camp in Chamberlain area Cedar shore's, American creek and happy campers are three commercialized campground in the township There are many places you can camp along the river for free Dude ranch is a free campground on the west side of the river dirt road great place to go Hope that helps

Happy Campers Campground is at the exit right before the rest area.