Alexander and I enjoyed the tour and probably spent a couple hours checking everything out. You might think a six year old would find it boring, but he actually was very interesting in a lot of what we saw. Of course, seeing as there were three pianos in the house (something my son loves!) helped a bit to keep him intrigued and excited. He even mentioned that he'd like to go back again someday!
(Review Disclaimer; I was not paid for my review of the Fenton Museum. We had free tickets to take the tour, but there was no monetary compensation and everything written are my personal feelings.)