@Comicsgate
To answer your question “Was The Green Dragon Inn of The Shire based on the Tavern where the American revolutionaries met in secret?
NO
The answer is in Letter 163:
“I first tried to write a story when I was about seven. It was about a dragon. I remember nothing
about it except a philological fact. My mother said nothing about the dragon, but pointed out that
one could not say ‘a green great dragon’, but had to say ‘a great green dragon’. I wondered why, and
still do. The fact that I remember this is possibly significant, as I do not think I ever tried to write a
story again for many years, and was taken up with language.”
It was taken from his youth, his mother’s words and her starting him on the path of language. Certainly a 7 year old British Boy would have no knowledge of Revolutionary Tavern.. Although given the name “The Green Dragon Inn” in all reality it was probably based at least loosely on “The Eagle and Child” the tavern the Inklings gathered at.
It is nice to have Tolkien’s letters look to for possible answers and this one appears to be spelled out to the Name a knod to his mother and if you look at the “Bird” the name they gave to “The Eagle and Child” it can quickly be compared, as it is where the Inklings played with ideas for their books and in fact, The Prancing Pony is where Frodo himself said “He was thinking of writing a book.”
Though the “Green Dragon” is in The Shire, It is only mentioned 5 times, between the Hobbit and LOTR, and not at all in Tolkien’s Letters or the Silmarilion.
Though some could argue its the Tavern in Bilbos Song. Though that is most certainly from the Nursery Rime “Hey Diddle Diddle” from 1765.