I am also searching an Isaac Goldsmith who was a successful Cigar dealer in Easton, Pennsylvania. He is first found in Easton in 1860 census records, noting his profession as "tobacconist." He married a Henrietta Weil and after an apparent service in the Civil War, resumed a very successful cigar business. There is much information available about him and his business.
It does not appear that he ever practiced in Boston. I don't know if he traveled though Holland or Britain, but it appears he was originally from Baden, Germany.