Yellowstone > Little Bighorn or Bighorns > Devil's Tower

Wonderful advice and factors to consider everyone. Sorry I wasn't clearer about destination... We are leaving Fishing Bridge in the morning with Devil's Tower KOA reservations that night, then on to Rushmore/Custer/Badlands the next few days. I just can't decide whether to do Bighorns or Battlefield. I saw both growing up (last time in my teens) but the family hasn't seen either one. I doubt we'll make the trip again before the kids are gone, so all this info helps. Thank you!