If you're a fan of Maud Hart Lovelace's Betsy-Tacy series, you'll be enchanted by the Betsy-Tacy Houses right in Mankato, which will be open for special tours during the conference. They're less than a mile from the conference site.
In addition, Mankato is in the heart of Laura Ingalls Wilder Country. Tack on a few days and turn the conference into just one stop on an extended Little House trip. Here's the drive time from Mankato to nearby Laura Ingalls Wilder sites:
Walnut Grove, MN: about two and a half hours
Burr Oak, IA: about three and a half hours (going right through Spring Valley, MN)
Spring Valley, MN: about two and a half hours
De Smet, SD: about five hours (driving right through Walnut Grove)
Pepin, WI: about three and a half hours
To orient yourself, here's a map with all of the local sites plotted on a map that includes Mankato: TBA