How much further you can go back depends on:

1) Your ancestors' names, occupations, place of residence and station in life. The ancestors of a Jasper Molestrangler who owned property in a rural village should prove fairly straightforward to research through wills, land records and, of course, parish registers. But a John Smith, labourer, in a major city is going to be very much trickier.

2) How much real research you want/are able to do. The resources available via Ancestry are wonderful, but they barely scratch the surface of what exists in repositories of various kinds around the country. But to use the latter you are going to have to (a) travel and (b) do some serious homework on the kind of records that were made, by whom and for what purpose.

3) The level of proof that you are comfortable with. With 19th century research and later, we are used to having corroborative evidence for most facts - a census entry matching an address on a birth certificate, a father's occupation in a baptism register matching that given on the child's marriage certificate etc. Other than wills (which are absolutely the best form of record in earlier centuries), data can be pretty sparse. So if you have a William Treehunter having children with a Mary and one of the children is baptised William Rellybasher Treehunter you can be fairly sure, when looking for a marriage, that the one between William Treehunter and Mary Rellybasher is probably the right one. But if the family is James and Sarah Taylor and their children have no interesting forenames, what do you do? Assume that the couple marrying in the local parish church a year or so before the baptism of their first known child are yours? It's reasonable, providing you have checked some surrounding parishes and there are no other possibles, but it ain't proof!

So your next step should probably be a comprehensive and detailed book - I would recommend Mark D Herber's Ancestral Trails. Once this has given you some food for thought on the kind of records that might exist, you can start tracking them down.

Hope this helps

Caroline