That's PA! I've been to King-of-Prussia
King-of-Prussia? I presume German settlers used to live there...?
Yes the NE has lots of states in such a small area but they are rich with history. You can easily visit all 6 "New England" states in one day but how much you would actually "see" would be another story.
You were in Pennsylvania! King of Prussia used to be famous for its huge shopping mall. I don't know if it still is. Or if its Frederick's is that Great.