Nice idea!
For Mr.'s general area....the Hilly Hundred near Bloomington IN. It's 50 miles each day of the weekend. It's pretty popular and has maybe 5,000. But it didn't seem too congested. Nothing compared to running the Chicago Marathon.
http://www.hillyhundred.org/GenInfo.html
However the Kentucky ride that Mak mentions look great and actually it's about the same distance from me. Maybe we can do BOTH.
"Being retired from Biking...isn't that kinda like being retired from recess?" Stephen Colbert asked of Lance Armstrong