Here's what he sent today.
Only place I know of is a range on the north side of Hawkeye Wildlife area, off of Amana Road. That would be around the NW corner of Coralville lake. Pistol, 50 yard rifle, 100 yard rifle, down the road an area to set up your own clay tosser, and a bow range.
That's a fair piece from Williamburg. That area is mostly gun friendly if you get away from the recent developments so the chance of finding a landowner who would let you shoot might be good.