This Isaac Simmons 1732?-1804 was one of the first Simmons to be documented in NC. Several sources suggest that he was a descendant of Moses Symondson who arrived in the Plymouth Colony in 1621, one year after the establishment of the colony. No source has been found that actually identifies a connection.
Under the "Plymouth Colony" section are the descendant charts of George Soles and Moses Symondson. Maybe this info will help someone one establish a connection.