Advice from anyone near Franklin, TN

My family is going to visit my parents in TN next month.  Ummm, how to put it nicely, there is usually nothing to do and I end up bored (blush blush).  So I am wanting to take the kids one day to Franklin, TN to see one or two of the Civil War museums.  Which ones do you recommend?  I would like to visit the one that was a field hospital and the one that has the battlefield attached (I read about that years ago, and now I can’t locate the info on it).  But I am open for suggestions from locals or those who have visited before.

Thanks for any input,

Paula