Yesterday the news section of this blog linked to this Crampton's Gap Battlefield tour. It should be noted that this tour is given by the state park service and by rangers pressed into history duty for the day; bless their hearts. Also, as previously noted here, Gathland State Park donations go into the park service's coffers not to helping the CG battlefield per se.
Please note that tours are also available from author Timothy Reese, certainly the expert of experts on this subject. See for yourself.