There is a restaurant with a car park less than half a mile up the road. that would be north on the A249 from Maidstone. Possibilities of parking there, but one a 'good' day it is usually full failry early
Also, there is White Horse Woods just opposite. it is £1.50 to park, but you would have to cross the A249 - not an easy task at all!! and quite dangerous!.
It finally stopped raining here about an hour ago, but there is still alot of surface and ground water around. Detling is like it's own little micro-climate!
the Kent show website now states the car park is limited tomorrow to members and pre-booked ticket holders only, so you may be ok! open at 8am, but closing at 4pm.
Take Wellies!!! and enjoy if you are going!