I have mixed feelings about NationalParkFinder. First, I'm glad NPS joined NationalParkFinder world, but they could have done so much more with this. For example, it would kick butt if trails were detailed on the map. While the description, picture and link to the parks' site are helpful, there are too many steps involved to get more information on them. I'd like to quickly pull up a park, see the trails (and whether or not they're dog-friendly) and be on my way, ready to explore. That type of feature would be especially handy on family road trips. The GW Parkway is listed as park, but it's also a long road, with parks within it, like Turkey Run, which has trails. If people could see that right away, it would just make more sense.
I suppose it depends what NPS's focus was in developing NationalParkFinder . I'm way to ADD to search through the parks NPS web site in order to peek at what trails are around the area. Some of their maps aren't very good. I didn't know the Mount Vernon trail intersected with so many others, until I ran it.
Handy app to have, though. Good starting point, NPS.