We're talking about a vacation this summer so we can plan ahead. My mother (who will pay for it) said she'd love to go to Yellowstone, but it looks like it's about a 24-hour drive for us. Still, I like the idea of going to a national park. We're in Indiana, so this image shows about the limits of where we're willing to drive. Maybe 14-15 hours at most, which puts most of the ones in the image in range.

However-

• We've already been to Indiana Dunes and Gateway Arch.

• My daughter is scared of caves, so Mammoth Cave is out.

Out of the rest, which would you most recommend so I can suggest it to my mother?

Is there anything not in Indiana that is within this area that you think is more worth visiting than a national park that also would take a decent amount of time to visit and see different things? (Not a city, obviously.)

Any advice appreciated. Thanks!