Another really interesting and educational site: National Parks park-finder. You can use the little "select box" to pick a park. Some have basic information, others, like my beloved Cuyahoga Valley N.P. (I grew up near there; it was a National Recreation Area when I lived there) have even more stuff. They have a wonderful tour of the "towpath" along the Ohio Canal. Takes me back to grade-school field-trip days and fall Saturdays spent hiking with my parents...