Nick
I only knew of one apprentice, An I don't recall where I found out that information.
As for Joshua Newbrough in Boone Co. The only Joshua I mentioned was Joshua White. I only mentioned him was sometimes one the eldest son is sometimes named after grandfather, I had heard.
Joshua Newbrough from Winchester. Va. did visit Boone County, from land records in Boone Co. an a mention in Winchester record "Joshua was away on a trip out west."
That about all I have. Maurice