Similar to Smoky Mountains....but Not All the Way to TN?

Well, there aren't mountains in MO... as you know.

However, Arkansas IS, at least a little bit. I might suggest the drive between Fayetteville and Ft Smith, Arkansas. There is a lake, and it's pretty.

ETA........
Or Branson.... It's an almost replica of Dollywood. I assumed you'd been there, but maybe not.

Ozark mountains
http://www.ozarkcabins.com/

Camp Ondensonk Cabins in southern IL - close to Carbonale. They have a bunch of 3 walled cabins!

Have you tried the Taum Sauk Mountains south of St. Louis?

Or Lake Wappapello State park?

I don't know if they have cabins but they do have camping.

have fun!