Richmond VA

Next summer I'm planning a rather ambitious RV trip from Western Canada to eastern USA. I'm a history nut and have planned to spend a few days in Gettysburg touring the site there and head down to Washington. I had originally planned to then head to Richmond for a few days after this, possibly take in Williamsburg while I'm there and then make my way to the Boston area. I'm just not sure if that little detour Richmond is worth the time. It adds about 500km and a few days to my trip. Is Richmond a place people would recommend going slightly out of their way to see? What about Williamsburg? Or, would people recommend just making my way to Boston directly from the Gettysburg area. Obviosuly there is a lot of person opinion that goes into a question like this, but I"m just looking for some thoughts. Thanks!!