Andy,
Shed Cat makes many valid points in his response.
A starting point bookwise might be this one :
http://www.ianallanpublishing.com/pr...3&cat=0&page=1 although it has its drawbacks notably the need for a jeweller's loupe to read it. LoL
For opening/closing/renaming dates you could do a lot worse than to acquire Railway Stations by R.V.J. Butt. It's long been out of print but I picked up a nearly mint ex-libris copy on fleabay for about sixteen quid a couple of years ago.
Gaining knowledge of the subject is, indeed, a very long process. My own interest stemmed from my luggage label collecting bug. It's all very well holding a piece of railways history in one's hand but where on earth is/was the station on the label and what became of it? It's proved to be a fascinating journey over a seven year period and showed up just what Shed Cat was suggesting. I thought I had an encyclopaedic knowledge of Britain's railways when I started collecting but that idea was quickly put to bed.
Your own immediate area (Guildford) isn't replete with abandoned railways although you do have the erstwhile ex-LBSCR line to Horsham to investigate. Check out Bramley & Wonersh, Cranleigh, Baynards, Rudgwick and Slinfold on that web site you've found.
One should bear in mind that abandoned stations and other old railway structures have become increasingly hard to find as most have been either demolished, redeveloped or turned into private residences as has been the case on the line mentioned above.
Mike M.