I've been to Ferry Farm before by myself and didn't think there was a lot to see there. It's predominantly an archaeological site, and there are no buildings on the property that were there during the time the Washington's lived there. In October, however, I took an out-of-town visitor there, and he helped me see it through new eyes. This is where George Washington spent much of his boyhood years. My friend was amazed at the opportunity to be able to walk the same ground as George did so many years ago.
There is a self-guided tour that provides a lot of the history and archaeology of the place - not just colonial, but Civil War too. This was the site of an encampment by the northern troops, and the location of one of the pontoon bridges during the Battle of Fredericksburg. You can walk down the old ferry road to visit the site of the pontoon bridge and view Fredericksburg across the river much as the Civil War soldiers and George Washington would have seen it. It's hard to imagine that, in the 1700s, this now placid river was filled with sailing ships bringing in goods from Europe and shipping out tobacco. Standing on the bank, one can try to look through Washington's boyhood eyes and think about the possibility of throwing a rock all the way across as he did (I couldn't!).
There's also a very nice garden here with plants that would have been grown in Washington's time. If you want to learn some things about the boy who became a legend, this is a great place to visit. If you have kids, they can run off a lot of energy here too! There are a couple of short, easy hiking trails, and if you're lucky, quite a lot of wildlife to see (especially birds). There are picnic tables too if you want to bring your lunch.