This is a good explanation of how hereditary surnames came to be in the UK, focusing mainly on location rather than linguistic derivations of names. The use of DNA in tracing surnames is also written about with a number of case studies which are a little complex but nonetheless worthwhile to read.
Trying to work out where your ancestors were before the census proper began in 1841 has always been a difficult process. You would normally have to rely on christening locations and notes and any wills.
The East Sussex Land Tax 1785 and its sister book the West Sussex Land Tax 1785 list all the occupiers and owners of dwellings and lands in each town and village in East Sussex. You will also be told how much the rental for the property is which will give you an idea of the size of it. Sometimes you will also be given extra pieces of information such as the name of the property which will help you to validate your finding.
A book well worth hunting around for, you can find it on Amazon and Ebay and the Sussex Record Society might still sell them as well.
The Reverend John Coker Egerton was the curate and rector of St Bartholomew Church in Burwash between 1857 and 1888. His diaries give a great insight into the village of Burwash at the time as well as some very important dates and information on baptisms, marriages and deaths of the local inhabitants.
This is a must have book if you have ancestors in Burwash. John Barkshire leads us through the history of Burwash and along the way includes information on a large number of Burwash inhabitants.