These are the ones I always hit (especially 1 and 2).
Z and S (which is the old Sauder's barn) in Denver Pa
http://zandsfabrics.com/
http://www.theoldcountrystore.com/ in Intercourse, Pa.
http://www.thequiltandfabricshack.com/ in Bird-in-theHand, Pa.
Zooks has another shop in Intercourse as well.
Here's a list for the general area:
http://www.quiltart.com/lancaster.html