We went during Westfield's maple syrup special event. Most of the heritage buildings were open and staffed by friendly and knowledgable volunteers who provided excellent historical interpretation. The printing house and the barn were my particular favourites. The sugar shack was open (with maple syrup samples!) as well as fluffy pancakes & succulent ham available for purchase.
Definitely worth visiting - it is a lot of fun for both adults and children alike!
Tip: buy your tickets online to save a small amount on the entrance fee. They are e-mailed to you immediately as a PDF.