I came across a list, starts in June though, not sure about May.
Jun 3-5 Ceder Rapids Trade Show Productions
Jan 11-12 Adventureland, Des Moines Trade Show Productions
Jan 24-26 Des Moines Trade Show Productions
Jan 31-Feb 2 Ceder Rapids Trade Show Productions
Feb 7-9 Sioux City, Ia RK Shows
Feb 14-16 Council Bluffs RK Shows
Feb 21-23 Des Moines RK Shows
Feb 28-Mar 2 Cedar Rapids RK Shows
Mar 15-16 Lake View, Ken McBride
Mar 21-23 Ceder Rapids Trade ShowProductions
Mar 21-23 Council Bluffs RK Shows
Mar 28-30 Council Bluffs, Ia RK Shows
Apr 4-6 Ottumwa RK Shows
April 11-13 Des Moines Trade Show Productions
Aug 9-10 Sioux City RK Shows
Aug 22-24 Cedar Rapids, Ia RK Shows
Nov 1-2 Adventureland, Des Moines Trade Show Productions
Dec 26-28 Cedar Rapids RK Shows