I am thinking  that  the 78 show was  Taylorville IL   then 79  was  Ladoga (south of Crawfordsville)

I am going to go from memory here...

75-- Malta
76--  Greenfield
77--- Iowa
78 --- Taylorville
79--  Ladoga
80--- Iowa
 
and  WB---I was  at the Ladoga show  2 days...  day 1 and 2...  maybe we crossed paths  and didnt know it.