After the death of her husband Edward, she did not remarry. She embarked on the ship Welcome to America in 1682, along with her son William and his family, her sons Edward and Thomas, and her daughter Ruth. On that trip Smallpox broke out, killing 60 of the 100 passengers. Since no records of them have been found in America, it is presumed that Joan and her sons Edward and Thomas were among the casualties.
http://chrisman.org/pedigree/out44.htm
There are some indications that Joan Bagham Buckman, went with her son, William Buckman, to Pennsylvania aboard the "Welcome" as a widow. However, General W. W. H. Davis, author of the History of Bucks County, Pennsylvania, appears to have seen the baggage memoranda cited as the source of Joan's travel to Pennsylvania. He believes that the first name of the widow was Ruth, not Joan....ie the sister rather than the Mother. He believed that the Buckmans of the baggage memoranda, who did not in his view include our William but another of the same name, spent their first winter in a cave south of Fallsington. In the Strawn family, who descend, of course, from the Buckmans, there was a strong tradition that their ancestors, supposed usually to have been Strawns, lived out their first winter in a cave on the bank of the Delaware. It is certain that many early Pennsylvanians who did live for such a time in such places, so this may represent a genuine tradition.
Ancesty - Patryka Tachick