Never used a guide... have always hunted private/public land with great success.
Anywhere around Mitchell up to Gettysburg area is great hunting.
Check this site out... lots of good info here (self-guided private):
http://www.uguidesdpheasants.com/
Outfitters:
http://www.huntingconnections.com/
(not sure if this is against forum rules, but it is the best source of outfitters for this area... remove it if necessary).