Elizabeth and Isaac moved to Yorkshire before they left for America (the 1871 census shows they took their sons George and Jacob with them). Yorkshire is so far away from Huntingdonshire, it seems an odd place to go if you wanted to maintain contact with your family. Even with a car today, it's a 4 or 5 hour drive at least, so I'm guessing they weren't planning on visiting their grown-up children too often! It looks as though they might have moved to the north of England in search of work, and then had a better offer of a new life in America. It would be interesting to know how this all came about - you can almost imagine them writing a letter saying they'd decided to emigrate to a Mormon town in Utah, and did anyone else fancy joining them? Both Isaac and Elizabeth were in their 60s when they left England, so they must have been brave and adventurous people. I will certainly be doing some more research about Paradise Cache and its settlers.
Merry Christmas from your distant cousin in the UK, Rebecca