I have reached the 17th century on a number of branches, through a combination of the parish registers, wills, using the A2A catalogue of archives, county histories, printed genealogies giving me clues where to look (I was lucky on that one - some of them were quite well-to-do). It takes a long time. I made a breakthrough this week to the late 17th century with one family, but it has taken me the better part of 15 years to get there.
Nell