Nebraska Wesleyan and Colorado College are exceptions. There are no single institutions (as opposed to leagues) that are more isolated than those two schools. To compare the plight of the WIAC, IIAC, MIAC, ASC, SCIAC,etc., to that of Nebraska Wesleyan and Colorado College is to do those two schools a grave disservice. WIAC teams have it easy in terms of finding regional non-conf D3 games compared to the Prairie Wolves and the Tigers.
Colorado College deserves kudos for trying so hard to conform to D3 scheduling specs. Nebraska Wesleyan, as you noted, stopped trying a few years ago.