of course you will want to find presenters, not just venues,
but here are a few links i googled...

Denver Area presenters..
http://www.swallowhill.com/

this place has a quote from Utah PHillips on their page
http://www.denverfolklore.com/history.htm

10 denver area venues here:
http://denver.metromix.com/facets/music/topic.music.music_genre.folk

Des Moines, this venue http://www.vaudevillemews.com/

Chicago,http://www.oldtownschool.org/

Cleveland,http://vineandbeancafe.com/, http://www.barkingspidertavern.com/

Albany--http://www.oldsongs.org/links.html this site has many links
this place in Saratoga Springs is historic...and i recently saw a
clip of Utah singing in the kitchen http://www.caffelena.org/ see:
http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=35049123

Maine. - it sounds like you got maine covered by mudcats..