The National Park Service website didn't lead me to expect much from this site, but we stopped since we were passing through, anyway.
We were pleasantly surprised at how well-developed and maintained the site is. Nothing to add to the other positive reviews, except that if you have kids, especially elementary- or middle-school-aged, don't forget to ask about the Junior Ranger program, available at most national parks. Kids get a free activity book and a Junior Ranger badge specific to the site. It's great for helping kids understand the history on their own level. The book at this site has more reading and activities than some others we've seen, and our daughter had enough to work on in the car after the visit.