I've never done this ride but I have done several TRIRI's that went through Brown County and the area is quite hilly. Living and riding around the Cincinnati area and used to lots of hills I still considered Bown County very hilly. One road, I can't remember if it was Bean Blossom or Bear Wallow I didn't even try to ride, I resigned myself to walking it.
The 25 mile route might not be so bad but I don't recognize any of the roads so I can't say for sure.