Every year, the RAGBRAI overnight towns are announced near the beginning of the year. Later in the year, first in June but now usually in March, a complete route is unveiled. Sometimes changes are made before the bikes hit the pavement.
Based on maps printed in the Register each year, I have compiled a listing of each year’s ride and each town visited, in order. This is an unofficial list. If ever you should find that my list and something from ride authorities disagree, listen to them (and correct me).
I haven’t parsed the list or maps to find out commonalities, but you can search for towns or strings of towns. For example, “Orange City, Alton, Granville” appears five times, and adding “, Marcus” at the end yields three results. (But there’s also one “Alton, Orange City” line.)