
There is no shortage of car parking, and there are shuttle buses from the car parks to the NEC itself. Parking charges are about £7 (NCP I believe, so charges are out of the KC's control). It's probably best to get there quite early because the queues to get to the NEC can be back onto the motorway round about 10am-ish.
The train is really easy - the station is at the NEC itself and you don't have to go out of doors at all (unless you're an exhibitor - dogs aren't allowed in the walkway to the exhibition centre).