ST5 9NY will get you to Hoon Avenue which is the road at the bottom of the school field. From memory you need to go to the roundabout and up the hill (Milehouse Lane) to the gate... but the track should be visible from Hoon Avenue assuming it is in the top corner like last year.
Of course I am not a Stoke club member so this advice is without warranty!
http://www.multimap.com/maps/?hloc=G...09NY|ST5%209NY
Neil