Earlham arranges shuttles (about every 2 hours) to the Dayton airport on the first two and last two days of Thanksgiving break, Christmas break, and spring break. They also have less frequent shuttles to the Indianapolis airport. There are no shuttles for the beginning or end of the school year, but it's possible to make arrangements with a local limousine service. Dayton is 45 minutes east on Interstate 70 while Indianapolis is an hour and a half west on I-70.
When we toured Earlham we flew into Cincinnati (the airport is on the Kentucky side of the Ohio River) and drove to Richmond. It's about 75 miles and mostly non interstate.
Our daughter has used the Dayton shuttle several times; she's had no problems. There's ride board in the student union, Runyon.
Here's the link to Earlham travel arrangements:
Earlham College –– Travel and Tourism
And YES, Earlham is definitely worth getting to! It's been a perfect fit for our daughter.