I did RAGBRAI one year. It's a bike ride across Iowa from West to East. There was a guy in our group that rode down from Minneapolis to do RAGBRAI. He rode totally self contained. I know there are a bunch or rides that are arranged around RAGBRAI either before or after. There's one that continues from the end of RAGBRAI through Illinois and into Chicago.
We have a bunch of Cycling associations and clubs listed in our directory.
Here's the link to the US Cycling section:
http://www.365adventure.com/adventur...ted_States.php