One use of the old Wisley airfield is for an annual bus rally of all the enthusiast-owned old buses around London, when you can get in and explore all round the field. Several hundred buses go there for which an old runway is obviously ideal. The 2008 event is in a couple of weeks time on Sunday April 6. There are old bus tours which drive along the runway in addition to the surrounding roads. If you can recall those old BEA and BOAC buses from the 1970s going out to Heathrow, or the even older generations of these, there are apparently some going to be shown.
http://www.lbpt.org/events.html