I'd take him to the White River, it would be a trip of the lifetime, but looking at the map it is around 700 miles so that would be a long haul from Cincinnati. The plus side is that you would be on some world famous trout water. You have some time you might checkout what the air fares are running. If it is in the budget, you then wouldn't have such a worry on the enroute wx. Checkout this shop:
Dally's Ozark Fly Fisher