Hello, I have family a LOT from Fuentes de Nava. some of them came to America. I have found a lot of information from ship manifest records. having family that came to America you are very lucky because you can find them much easier. check out http://www.ellisisland.org
since you are also a subscriber to ancestry.com you can freely save and access the same records that are on ellis island website, and ancestry.com has a much better viewer to view and save the records. also, in addition to that interview family members who are the oldest. they will have a wealth of information that you can use to spot misspellings in surnames and assist you to find your ancestors much quicker. feel free to contact me with any other questions. I've been researching since 2002.Good Luck!