Rockford, IL....2 hours to SFGAm, 1.5 to Little A-Merrick-A, 3 to Big Chief's, and about 4.5 to Indiana Beach. (though I still haven't gotten around to visiting the last 3 parks.)
McDonald, OH
40 mins from SFWoA Too far from CP 1 1/2 hour to Kennywood. 1 hour to Conneaut Lake
----------------- Six Flags, the only chain of parks that can manage to have stacking with a one train operation.