My line of the Rieff/Rife's came over in 1753 to Lancaster County (became Adams County).David Rieff (born ca. 1751)was a member of Captain Hughey's Lancaster County Militia during the Revolutionary War. He later became a Mennonite preacher. I have not been able to validate any of this early information as I have been researching other lines.Potentially your Rife's may be cousins of mine as many times families would send money back to Europe to pay the passage for additional family members. The person that did the research also states that there was a David Rieff who came over in 1734 and he couldn't determine from the records whether this was the same family, etc.So I would not put any faith in the early documents.
David's son, Samuel (1788-1856), moved to Ontario, Canada in 1823.All my information is from that point on.
I know that on several sites (Ancestry.com, etc) there are additional Rife families dating back to that time.