Great Comprehensive Directory: Cohen's Free Online European Birth & Baptism Databases
Before you try to move back in the records:
I. Make certain you have done all you can in America or Canada before backing up across the ocean. Advice for that is on the Immigrant Ancestors page
2. Get prepared to work in a new country - look for:
Guides to researching in that country - a great place to start for this is usually the FamilySearch Wiki for Europe which will often point you to more resources.
In the directory of topics to the left pay special attention to these subjects:
Church Records
Customs
Handwriting
Language and Languages
Names, Personal
Find good maps. There are wonderful historical maps and detailed town maps online. Use terms like maps, gazetteers, atlas along with place names. Google image search often speeds this process up.
Yorkshire maps
Adding the term "historical" sometimes digs further for older maps.
Find some history. If you know the town or general area where your ancestor was from Google the town along with the term history such as
Elland Yorkshire England
you will probably get several pages that give some historical overview of the place and may signal some other historical event you should explore to better understand families that lived there.
3. Check the International Genealogical Index (IGI) which indexed thousands and thousands of parish records throughout the world. Keep in mind that some records are indexed from source records and some were submitted as people's research (which may be wrong)