Hey, Jeff, My husband's name is also Jeff, but our last name is a slightly different spelling. There is also a Dr. Jeff Postlewaite(sp?)that was interviewed by Time(?) magazine a number of years ago. There are many variations of the name, but we are all related, traced back to at least the 1600's in England.
Actually I just came across your post from 2 years ago so I don't know if your question about the tavern has been answered. The tavern is still standing. It is a private residence, and has been in the Fehl family since the late 1700's. From what I understand, they do welcome Posties visiting the place. I hope I am not wrong about that info.
We have not had the opportunity to visit that area of the East Coast(we are in California). Several of my husband's sibling, however, did visit Millom, England where the 1st John Postlethwaite lived before he came to the Colonies around 1708(?).
The person who has the most information on the Postlethwaites is Dilmond Postlewait and he does answer queries on this site. It has been a wonderful journey exploring our ancestors pasts. I hope you have fun doing the same. Evalyn